15. Heroes and Villains from World War II: Codebreakers, Spies, and Intelligence Operations

My Name is William J. Donovan: The Intelligence Organizer

I was born in Buffalo, New York, in 1883, the son of Irish-American parents. I learned early that advancement required discipline, education, and a willingness to work harder than the next fellow. I attended Columbia University, studied law, and built a successful legal career. The law taught me something that later proved useful in intelligence work: facts rarely arrive neatly arranged. You gather evidence, question its reliability, determine what is missing, and then make the strongest judgment the evidence permits.

Wild Bill Goes to War

When America entered World War I, I served with the 165th Infantry Regiment, formerly New York's famous Fighting 69th. Combat is an unforgiving instructor. I was wounded and decorated for actions under fire, eventually receiving the Medal of Honor for leadership during fighting in France. My men began calling me "Wild Bill," although I was never particularly fond of the nickname. What mattered was the lesson: commanders make decisions with incomplete information, and bad information can be every bit as dangerous as enemy gunfire.

Lawyer, Traveler, and Observer

After the war, I returned to law and public service, but I continued watching events overseas. During the 1930s, dictatorships expanded their power while another European war approached. I traveled widely and observed political and military conditions firsthand. I became convinced that the United States needed something it did not yet possess—a centralized organization capable of collecting foreign intelligence, analyzing it, and placing useful conclusions before the nation's leaders.

Building an Intelligence Organization

In 1941, President Franklin D. Roosevelt appointed me Coordinator of Information. After the United States entered World War II, that effort evolved, and in June 1942 I became director of the newly created Office of Strategic Services, the OSS. We recruited an unusual collection of Americans: lawyers, professors, economists, linguists, soldiers, journalists, scientists, mapmakers, and people who simply possessed skills the enemy did not expect a spy to have. Intelligence demanded more than men in trench coats. We needed people who understood languages, cultures, industries, transportation systems, politics, and human behavior.

The OSS Goes to War

The OSS gathered intelligence and conducted special operations in Europe, Asia, and other theaters. Our personnel worked with resistance movements, infiltrated enemy-controlled territory, collected documents, studied economies, created maps, and helped sabotage enemy operations. Some carried weapons. Others carried radios, forged papers, cameras, or notebooks. We learned that information could be a weapon when placed in the right hands at the right moment. A commander who knows what lies beyond the next hill possesses an advantage before the first shot is fired.

Turning Information into Intelligence

Collecting secrets was only half the job. Reports arrived from agents, intercepted communications, diplomats, military units, resistance fighters, newspapers, photographs, and countless other sources. Much of it was incomplete, contradictory, or simply wrong. Our analysts had to compare those fragments and determine what they meant. I wanted intelligence that reached beyond counting tanks. Why was the enemy moving them? What could his factories replace? What did local populations believe? What might he do next? Information becomes intelligence only after disciplined minds give it meaning.

When the war ended in 1945, the OSS was dissolved. I believed that was a mistake if America returned permanently to its old habits. Modern threats did not disappear merely because armies stopped shooting. I argued that the United States needed a permanent, centralized foreign intelligence service. I did not become director of the Central Intelligence Agency when it was established in 1947, but many OSS veterans, methods, and ideas helped shape the American intelligence community that followed.

The Secret War Begins: Intelligence Networks Before WWII - Told by Donovan

Long before German tanks crossed into Poland in September 1939, another struggle was already taking place behind locked doors, inside embassies, aboard ships, along borders, and through coded radio transmissions. Governments wanted answers to questions that could determine whether nations survived: How large was the enemy's army? What weapons was he building? Who were his allies? Where would he attack? During the 1930s, as Germany, Italy, Japan, the Soviet Union, Britain, France, and other powers watched one another with growing suspicion, intelligence became one of the quiet battlefields preparing the way for the coming war.

Spies Were Only One Piece

When most people hear the word intelligence, they imagine a secret agent stealing documents. That happened, but intelligence networks were considerably larger. Military attachés observed foreign armies. Diplomats reported political developments. Naval intelligence followed fleets and shipping. Governments intercepted radio communications, examined aerial photographs, questioned travelers, studied newspapers, and recruited human sources. Counterintelligence officers had the opposite assignment: discover who was spying on them. A useful intelligence service had to collect thousands of fragments and determine which ones were important, which were misleading, and which were deliberately planted by an adversary.

Europe's Intelligence Machines

Britain already possessed experienced organizations such as the Secret Intelligence Service, commonly called MI6, for foreign intelligence, while MI5 concentrated on security and counterintelligence at home. Germany reorganized and expanded its own intelligence and security apparatus after Adolf Hitler came to power, with the military Abwehr operating alongside increasingly powerful Nazi security organizations. France maintained military intelligence networks, while the Soviet Union developed extensive foreign espionage operations. These services competed not only to steal military secrets but also to recruit officials, penetrate political movements, identify potential enemies, and discover what other governments intended to do.

The Invisible Battle Over Codes

Some of the most important intelligence officers never met an enemy agent. They attacked mathematics instead. Nations increasingly depended upon radio, which meant military orders could travel rapidly—but enemy listening stations could intercept those signals as well. Encryption machines and complicated codes were therefore developed to protect messages. Poland achieved one of the greatest prewar intelligence breakthroughs when mathematician Marian Rejewski and his colleagues Jerzy Różycki and Henryk Zygalski developed methods for attacking Germany's Enigma cipher system. In July 1939, with war approaching, Polish experts shared vital Enigma knowledge with British and French representatives. That decision would have enormous consequences.

America Watches From the Sidelines

The United States possessed military and naval intelligence organizations, but it did not yet have a single centralized foreign intelligence service comparable to what would later emerge during the war. Information was scattered among government departments and military organizations. From my perspective, this was dangerous. A nation might possess several pieces of an enemy's plan while failing to recognize the picture because those pieces rested on different desks. Intelligence had to be gathered, compared, analyzed, and delivered to leaders capable of acting upon it.

The Most Dangerous Question

By the late 1930s, intelligence services possessed mountains of information about German rearmament, Japanese expansion, Italian ambitions, Soviet activities, and Europe's political instability. Yet intelligence cannot make decisions for governments. Leaders still had to decide what the evidence meant. Was an enemy bluffing? Was a troop movement preparation for invasion or political intimidation? Was an informant trustworthy? Those questions became increasingly urgent as Germany absorbed Austria in 1938, dismantled Czechoslovakia, and turned its attention toward Poland.

When Germany invaded Poland on September 1, 1939, the visible war began in Europe. The invisible one had already been underway for years. Agents would now move across borders under false identities. Radio operators would transmit from hidden rooms. Mathematicians would attack encrypted messages. Resistance movements would construct clandestine networks, and governments would deliberately feed false information to their enemies. Eventually, I would help create America's Office of Strategic Services to participate in that struggle. But none of us invented the secret war in 1942. We inherited a battlefield that had been forming quietly throughout the 1930s—and once the shooting began, information would become a weapon almost as important as steel.

My Name is Alan Turing: The Codebreaker

I am a mathematician, logician, and codebreaker. I was born in London in 1912, though much of my childhood was spent at school while my parents traveled between Britain and India. I was not particularly interested in doing things simply because teachers said they ought to be done. I preferred problems. Numbers behaved according to rules, and if one understood the rules properly, rather complicated questions could sometimes become remarkably simple. At Sherborne School, I became fascinated by mathematics and science, even when those subjects were not considered the most important parts of a gentleman's education.

Mathematics and Machines

I studied mathematics at King's College, Cambridge, where I became increasingly interested in a peculiar question: what does it actually mean to calculate something? In 1936, I described an imaginary machine that could read symbols, follow instructions, and perform calculations one step at a time. Today, you might recognize the basic idea as something resembling a programmable computer. I was not trying to invent a machine for people to keep on their desks. I was attempting to understand the limits of mathematical calculation. Nevertheless, sometimes a theoretical question turns out to have exceedingly practical consequences.

A War of Secrets

When Britain entered the Second World War in September 1939, I went to Bletchley Park, where mathematicians, linguists, chess players, engineers, and others were attempting to understand Germany's encrypted communications. The Germans used machines such as Enigma to scramble military messages into apparent nonsense. Polish mathematicians, particularly Marian Rejewski, Jerzy Różycki, and Henryk Zygalski, had already made extremely important breakthroughs against Enigma and shared their knowledge with Britain and France before the war. Our task was to take that work further as German procedures and machines continued to change.

Breaking Enigma

At Bletchley Park, I worked especially on German naval Enigma. The difficulty was rather impressive. Enigma could be configured in an enormous number of ways, and the settings changed regularly. Trying every possibility by hand would have been absurdly slow. Gordon Welchman and I helped develop methods associated with the bombe, an electromechanical machine designed to eliminate impossible Enigma settings rapidly. Machines did not replace human reasoning; they allowed us to perform the repetitive portions of a problem quickly enough for human reasoning to become useful.

The Battle Beneath the Battle

The information obtained from decrypted enemy communications became known through the highly secret Ultra intelligence system. It could reveal information about German military movements and, particularly important to my work, U-boat operations threatening Allied shipping in the Atlantic. But knowing a secret created another problem: if we acted too obviously upon everything we discovered, the Germans might realize their communications had been compromised. Intelligence therefore required mathematics, engineering, patience, secrecy, and judgment. Solving the cipher was only the first part of the problem.

Thinking Beyond Enigma

My wartime work eventually extended beyond Enigma. I became interested in speech encryption and traveled to the United States to examine secure communications technology. After the war, I returned to a problem that had interested me for years: whether machines could perform activities we normally associate with human thought. I worked on early computer designs and eventually proposed what became known as the Turing Test—a practical way of considering whether a machine's conversation might become indistinguishable from that of a person. I found the question "Can machines think?" rather badly defined. Better questions often produce better science.

Bletchley Park and the Race to Break Enigma - Told by Alan Turing

When I arrived at Bletchley Park in September 1939, shortly after Britain entered the war, there was nothing particularly heroic-looking about the place. It was a country estate in Buckinghamshire, roughly halfway between London and Oxford, filled with an unusual collection of mathematicians, linguists, chess players, engineers, classicists, and military personnel. Yet inside its mansion, huts, and later blocks, we were attempting something extraordinarily important: reading encrypted German communications before the information became useless.

A Puzzle That Changed Every Day

The German Enigma machine did not present us with one puzzle that could simply be solved and forgotten. Operators used changing settings, and different German military organizations operated separate communications networks. Even if we determined how messages were being encrypted on one network, tomorrow could present a new problem. Naval Enigma was particularly important to my work because German U-boats threatened the merchant ships carrying food, fuel, weapons, and other supplies across the Atlantic to Britain. A decrypted message about a submarine's position might help save ships—but only if we solved it quickly enough.

We Did Not Begin Alone

One fact must never be forgotten: Polish cryptanalysts had attacked Enigma before us. Marian Rejewski, Jerzy Różycki, and Henryk Zygalski developed mathematical methods for understanding the machine, aided by intelligence obtained through the French. In July 1939, Poland shared crucial knowledge with Britain and France, including reconstructed Enigma machines and techniques for attacking the cipher. Their work gave us an invaluable foundation. At Bletchley Park, we had to build upon it while responding to continuing German changes.

Building the Bombe

Trying every possible Enigma setting individually was hopelessly inefficient, so we needed machinery to help eliminate impossible possibilities. Building upon earlier Polish ideas, I developed a design for what became the British bombe, while Gordon Welchman contributed an important improvement known as the diagonal board. Engineer Harold "Doc" Keen and the British Tabulating Machine Company turned these ideas into working machines. The bombes did not simply print out German messages in English. Instead, they rapidly tested logical possibilities, helping us identify promising Enigma settings that human cryptanalysts could investigate further.

Humans Against the Machine

Our greatest advantage was often not a machine at all—it was human behavior. German operators sometimes used predictable phrases or followed routines. Weather reports, military terminology, repeated expressions, and known circumstances could provide us with probable pieces of plaintext known as cribs. We could test these guesses against intercepted ciphertext. Enigma also had a useful weakness: it could never encrypt a letter as itself. One impossible letter could therefore destroy an entire hypothesis. It was rather satisfying to eliminate thousands of possibilities because one small piece of logic said they could not be correct.

When the Codes Went Dark

There were moments when German changes suddenly made communications unreadable. German naval Enigma became still more difficult when the U-boat service introduced a four-rotor version in 1942. For months, important Atlantic communications became largely inaccessible to us. Captured German codebooks and cipher materials from vessels and U-boats, combined with continued cryptanalytic work, proved enormously valuable in restoring access. This illustrates something frequently misunderstood about codebreaking: mathematics was essential, but so were captured documents, intercepted radio signals, operator mistakes, engineering, and intelligence gathered at sea.

The Secret Called Ultra

Information obtained from high-level decrypted enemy communications was distributed under exceptionally strict security and became associated with the designation Ultra. Protecting the source was vital. If Germany discovered that Enigma traffic was being read, procedures or machines could be changed and our advantage might disappear. Intelligence therefore created an uncomfortable problem: sometimes knowing something did not mean one could act upon it in the most obvious way. The enemy must not discover how much you know.

People sometimes remember Bletchley Park through a handful of famous names, but the operation eventually depended upon thousands of people, many of them women. They intercepted messages, operated bombes, translated German, maintained machines, catalogued information, analyzed traffic, and performed countless other tasks. We were not solitary geniuses defeating Enigma with pencil and paper. We were part of an enormous intelligence system in which mathematics, engineering, organization, captured material, and human judgment worked together.

Signals Intelligence: Listening to the Enemy - Told by Alan Turing

One of the peculiarities of modern warfare is that an enemy may reveal a considerable amount simply by communicating. During the Second World War, armies, ships, aircraft, headquarters, and submarines depended upon radio to coordinate operations across great distances. Radio was wonderfully useful because a message could cross hundreds of miles without a physical wire. Unfortunately for the sender—and fortunately for people in my profession—the same signal could often be heard by anyone equipped to listen. Thus began a remarkable contest: transmit enough information to command your forces while preventing the enemy from discovering what you are saying.

Thousands of Ears Were Listening

Britain established an extensive network of wireless interception stations where operators searched the airwaves for enemy transmissions. Many intercept operators belonged to the Women's Royal Naval Service, Women's Auxiliary Air Force, and other organizations. They carefully recorded streams of letters, numbers, Morse code, call signs, frequencies, and transmission times. The operators usually could not understand the encrypted messages themselves. Their responsibility was to capture them accurately and quickly so that the material could be sent onward for analysis. A single incorrectly copied character could complicate the work considerably.

A Message Can Speak Without Being Read

Suppose you intercept a German radio message but cannot decipher a single word. Is it useless? Not at all. We could study where transmissions originated, which stations communicated with one another, how frequently messages appeared, what call signs were being used, and whether radio activity suddenly increased or disappeared. This became known as traffic analysis. An unusual burst of communications might suggest that military units were moving or preparing for operations. Silence could be significant as well. In intelligence, sometimes the envelope tells you something even when you cannot open the letter.

Finding the Transmitter

Radio signals could also betray their location. Direction-finding stations could determine the approximate direction from which a transmission originated. Comparing bearings taken from different locations could help estimate the transmitter's position. This became particularly valuable during the Battle of the Atlantic, where Allied forces attempted to locate German U-boats communicating by radio. The Germans needed those communications to coordinate submarine operations, yet every transmission created a possibility that someone else was listening. The longer one transmitted, the greater the opportunity for detection.

From Interception to Bletchley Park

Intercepted encrypted traffic eventually reached places such as Bletchley Park, where specialists attempted to understand it. Different German services used different systems, networks, procedures, and encryption methods. Our work against Enigma therefore formed only one part of a much larger signals-intelligence operation. Cryptanalysts searched for weaknesses, engineers developed equipment, linguists translated recovered text, and analysts compared decrypted messages with information from other sources. A message was rarely valuable simply because we could read it. We had to determine who sent it, why it mattered, and how urgently someone needed to know.

The Atlantic's Invisible Battlefield

Signals intelligence became especially important in the Atlantic. German U-boats threatened the merchant convoys upon which Britain depended for survival. German submarine headquarters communicated with boats at sea through encrypted radio transmissions, while Allied intelligence attempted to intercept, locate, and sometimes decipher those communications. When German naval messages could be read, intelligence could help identify submarine patrol areas and contribute to decisions about convoy routes. But when German encryption procedures changed, our window into their communications could suddenly close.

The Enemy Was Listening Too

One should not imagine that signals intelligence belonged exclusively to the Allies. Germany, Japan, Italy, the Soviet Union, and other nations maintained their own interception and cryptanalytic organizations. Allied radio operators therefore had to assume that someone on the opposing side might be listening. Poor radio discipline, unnecessary transmissions, repeated phrases, and insecure procedures could provide an enemy with valuable clues. Every radio message was therefore both a tool and a risk.

The Mathematics of Listening

People often imagine intelligence as a spy quietly opening a safe. Signals intelligence could be considerably less dramatic to watch: operators wearing headphones, sheets covered in seemingly meaningless characters, mathematicians examining patterns, and machines repeatedly testing possibilities. Yet behind those symbols might be the position of a submarine, the movement of an army, or the plans of an air unit. The lesson was wonderfully simple. You did not always have to stand behind enemy lines to discover what the enemy was doing. Sometimes you merely had to listen carefully enough—and know what the patterns were trying to tell you.

America Builds an Intelligence Service: Donovan and the OSS - Told by Donovan

When the Second World War began in Europe in 1939, the United States possessed intelligence organizations, but we did not have one central civilian organization responsible for gathering and analyzing foreign intelligence on the scale the coming war would require. The Army had intelligence. The Navy had intelligence. The State Department gathered diplomatic information. The FBI handled important security and intelligence responsibilities. But information scattered across different offices can become almost as dangerous as having no information at all. I became convinced that America needed an organization capable of assembling those pieces into a larger picture.

Learning from the British

Before America entered the war, President Franklin D. Roosevelt sent me overseas to observe conditions in Europe and the Mediterranean. I traveled to Britain and elsewhere, meeting officials and studying how the British organized intelligence and special operations. Britain had spent generations developing overseas intelligence networks and now faced Nazi Germany directly. I returned convinced that America needed a coordinated system capable not merely of collecting secrets, but of analyzing political, military, economic, and social information. A general needs to know where the enemy's tanks are, certainly, but he should also know whether the enemy can replace those tanks.

The Coordinator of Information

In July 1941, Roosevelt appointed me Coordinator of Information, or COI. This new organization brought together people who might never have imagined themselves working in intelligence. We recruited historians, economists, lawyers, journalists, geographers, scientists, linguists, military veterans, and specialists familiar with foreign countries. Some would eventually work behind enemy lines. Others might never leave Washington. Both could be valuable. A professor studying German oil production might reveal a vulnerability just as important as information carried across a border by an agent.

Pearl Harbor Changes Everything

Then came December 7, 1941. Japan attacked Pearl Harbor, and the United States entered the war. The intelligence failures surrounding the attack demonstrated painfully how dangerous fragmented information and poor coordination could be. There had been warnings and intercepted information before the attack, but possessing pieces of information was not the same as assembling them into an accurate warning in time. America was suddenly fighting a global war, and we required intelligence from Europe, North Africa, Asia, and beyond. The work had become considerably larger than anything we had originally planned.

The Birth of the OSS

In June 1942, Roosevelt established the Office of Strategic Services, the OSS, under the Joint Chiefs of Staff, and I became its director. The organization gathered foreign intelligence, conducted research and analysis, supported resistance movements, and carried out special operations. We recruited an extraordinary range of people. Some were trained to parachute into occupied territory. Others forged documents, operated radios, prepared maps, studied enemy industries, or analyzed reports. Future chef Julia Child even served with the OSS, working in administrative and technical roles. Intelligence did not require everyone to look or think alike. Quite the opposite—we needed people who noticed things others overlooked.

Behind Enemy Lines

OSS personnel eventually operated across Europe and Asia. They worked with French resistance groups, gathered information in occupied countries, supported guerrilla forces, and entered dangerous territory to observe enemy activity firsthand. Jedburgh teams, composed of specially trained Allied personnel, parachuted into occupied Europe to work with resistance forces. In Burma, OSS Detachment 101 cooperated with local fighters and gathered intelligence against Japanese forces. These missions could provide commanders with information no aircraft photograph or intercepted radio message could supply.

The Analysts Behind the Agents

Yet I never wanted the OSS to become merely an organization of daring spies. Our Research and Analysis Branch employed scholars who examined maps, population statistics, industrial production, transportation networks, political movements, and enemy economies. Imagine receiving reports from ten different agents, aerial photographs, intercepted communications, and shipping records. Someone must determine how those pieces fit together. Collection gives you facts. Analysis attempts to tell you what those facts mean.

An American Experiment in Intelligence

The OSS was imperfect, sometimes unconventional, and occasionally involved in operations that produced mixed results. We were building a new organization while simultaneously fighting a global war. But we demonstrated something important: intelligence could be organized as a coordinated national effort combining human agents, scholars, technology, military operations, and analysis. The OSS would be dissolved in 1945, but its story did not simply end. Many of its people and ideas influenced the intelligence system that followed, including the Central Intelligence Agency established in 1947. America had entered World War II without a centralized foreign intelligence service. By the war's end, we had learned that in the modern world, understanding an enemy could be nearly as important as defeating him on the battlefield.

My Name is Juan Pujol García: The Double Agent

I was born in Barcelona, Spain, in 1912, and before anyone imagined me as a spy, I lived a rather ordinary life. Then Spain descended into civil war. I disliked the brutality and extremism I witnessed from both sides, and the experience left me deeply suspicious of dictatorships. When another war spread across Europe and Adolf Hitler's Germany appeared increasingly powerful, I decided that I wanted to help Britain. There was one difficulty: Britain had not asked for my help.

Becoming a Spy Without Permission

I approached the British and offered to work for them, but they rejected me. I could have stopped there. Instead, I devised another plan. I approached German intelligence and persuaded them that I was willing to spy on Britain. They accepted me. The Germans believed I would travel to Britain and report what I discovered, but I actually went to Lisbon, Portugal. From there, using newspapers, maps, travel guides, and my imagination, I began sending them reports about a country I had barely seen.

An Army of People Who Never Existed

A spy needs sources, so I invented them. I created imaginary agents scattered across Britain—soldiers, workers, travelers, and people supposedly positioned near important ports and military installations. These individuals had personalities, occupations, expenses, and sometimes personal troubles. When information arrived late, I invented reasons. At one point, an imaginary agent even died, and I arranged for his equally imaginary widow to require financial assistance. The Germans continued paying for a network composed largely of people who existed only inside my reports.

The British Finally Listen

Eventually, British intelligence discovered what I was doing and recognized that my deception could be useful. In 1942, I was brought to Britain and began working with MI5. My British codename became GARBO because my case officer thought my performance worthy of the great actress Greta Garbo. Working with Tomás Harris, I transformed my fictional network into an increasingly elaborate intelligence operation. The objective was not simply to tell lies. A convincing deception requires truth. We sometimes provided genuine information, carefully delayed or selected so that the Germans would continue trusting me without gaining a useful advantage.

Playing Two Sides

The Germans believed I was their loyal agent in Britain. The British knew I was actually working for them. This placed me within the Double-Cross System, through which captured or cooperative German agents were used to send controlled information back to Germany. Every message had to make sense when compared with previous messages. One contradiction could destroy years of work. Espionage was not merely disguises and secret meetings. Much of it was memory, paperwork, timing, psychology, and understanding what another person already wanted to believe.

The Great Deception

My most important assignment came before the Allied invasion of France in 1944. The Germans knew an invasion was coming, but they did not know exactly where. The Allies wanted them to believe that Normandy was not the principal target and that another, larger invasion would strike near the Pas-de-Calais. Through Operation Fortitude and the wider Allied deception effort, false military formations, misleading radio traffic, physical deception, and double agents created an enormous illusion. My fictional network became one piece of that deception.

D-Day and the Lie That Continued

When Allied troops landed in Normandy on June 6, 1944, my work was not finished. I continued reporting to the Germans and reinforced the claim that Normandy was a diversion while the supposed main invasion force remained in Britain. German commanders had many sources influencing their decisions, and no single spy controlled their response, but the deception campaign helped strengthen German uncertainty about Allied intentions. Remarkably, German intelligence continued to trust me.

Honored by Both Sides

There was an extraordinary irony to my career. Germany awarded me the Iron Cross for my supposed service to the German war effort. Britain later made me a Member of the Order of the British Empire for helping defeat Germany. Few people can say they were decorated by opposing sides in the same war while remaining loyal to only one of them. After the war, I feared possible retaliation. I eventually allowed reports to circulate that I had died and began another life in Venezuela, far from the intelligence world.

The Strange Responsibility of Deception

Years later, my true story became publicly known, and I returned to Britain before my death in 1988. I had spent the war lying professionally—creating people who never existed, reporting events that had not happened, and convincing intelligent men to trust information deliberately designed to mislead them. I do not apologize for helping oppose a dictatorship I believed threatened Europe, but deception is never something to celebrate carelessly. Behind our messages were real soldiers whose lives depended upon decisions made from imperfect information. If my story teaches anything, it is that intelligence is a battle over belief, and whoever understands what an opponent expects to see may sometimes influence what that opponent believes is true.

Double Agents and the Double-Cross System - Told by Juan Pujol García

The finest lie is not the most fantastic one. It is the lie surrounded by enough truth that the listener decides to believe it for himself. During the Second World War, Britain developed an extraordinary intelligence operation known as the Double-Cross System. German agents sent to Britain could be identified, captured, and in some cases persuaded to work for British intelligence instead. Germany believed these people were spying on Britain. In reality, British intelligence could use them to influence what Germany thought it knew. I became one of those double agents, although my journey into that strange world began differently from most.

I Volunteered to Become Germany's Spy

I wanted to help Britain fight Nazi Germany, but when I first offered my services to the British, they were not interested. So I approached German intelligence instead. I convinced the Germans that I could spy for them and was given training, money, secret communications methods, and the codename Arabel. There was one rather important problem with my assignment: I was supposed to be operating inside Britain, but initially I was actually in Lisbon, Portugal. I therefore began constructing reports about Britain using newspapers, maps, reference books, railway timetables, and imagination.

My Agents Did Not Exist

One spy could only see so much, so I invented an entire network. I created fictional subagents supposedly living throughout Britain and gave them occupations, personalities, political opinions, travel habits, and relationships. Some were supposedly unreliable. Others were enthusiastic. Their reports occasionally arrived late because of imaginary difficulties. One fictional agent even died, requiring me to explain his absence and eventually arrange support for his imaginary widow. The Germans paid expenses for members of my network who had never drawn a breath. The deception worked because the stories were detailed enough to appear human.

Britain Discovers GARBO

British intelligence eventually realized that someone was sending Germany false reports and reconsidered my earlier offer. In 1942, I reached Britain and began working with MI5. My British codename became GARBO, a reference to actress Greta Garbo, because my ability to perform different identities impressed my handlers. Working closely with my case officer, Tomás Harris, I expanded my imaginary organization until German intelligence believed I controlled a substantial network of sources. Now my reports could incorporate carefully selected real information alongside invention.

How Double-Cross Worked

Britain's Double-Cross System was overseen through the Twenty Committee, whose name itself was a joke: the Roman numerals for twenty, XX, formed a "double cross." British authorities had identified German agents operating in Britain and turned a number of them into controlled double agents. Their communications with Germany could then be carefully managed. But we could not simply send falsehood after falsehood. If everything an agent reported proved incorrect, Germany would stop trusting him. Sometimes accurate information was transmitted when it was already too late for the Germans to act upon it. Trust was a resource, and we spent it carefully.

The Enemy Must Believe You

Every deception faced the same difficulty: the Germans had other sources of information. My reports therefore had to agree with facts they could independently confirm. If I claimed that an army division was in Scotland when German reconnaissance clearly placed it elsewhere, suspicion might destroy the entire operation. We built stories from many small details and allowed German intelligence officers to reach conclusions from them. That was far more convincing than simply announcing what we wanted them to believe.

Preparing for the Greatest Deception

By 1943 and 1944, the Allies faced an enormous intelligence problem. Germany knew that an invasion of Western Europe was coming. Hundreds of thousands of troops, ships, aircraft, and vehicles were assembling in Britain. Hiding the existence of an invasion was impossible. Instead, Allied planners sought to conceal where and when the main blow would fall. Double agents became one element of a much larger deception effort. False radio traffic, dummy formations, controlled information, and misleading military activity could create a picture of Allied intentions that Germany might accept.

My Name is Noor Inayat Khan: The Wireless Operator Behind Enemy Lines

I was born in Moscow in 1914 to an Indian father and an American mother, and I grew up largely in France. My father, Hazrat Inayat Khan, was a musician and spiritual teacher who taught us about peace, compassion, and the dignity of human life. I was quiet by nature and loved music and writing. I studied child psychology and music in Paris and wrote stories for children. Nothing about those early years suggested that I would one day carry a secret radio through German-occupied France.

War Changes My Direction

When Germany invaded France in 1940, my family escaped to Britain. I believed deeply in nonviolence, yet I also believed that allowing tyranny to triumph without resistance was unacceptable. My brother Vilayat and I decided that we must help oppose Nazi Germany. I joined Britain's Women's Auxiliary Air Force and trained as a wireless operator. Radio work required concentration, accuracy, and speed. A single incorrect letter could alter a message, and during wartime, a mistake could endanger lives.

Becoming a Secret Agent

In 1943, I was recruited into the Special Operations Executive, or SOE, the British organization that sent agents into occupied countries to support resistance movements and gather information. Some questioned whether my gentle personality made me suitable for dangerous undercover work. Others noticed that I spoke French fluently and was already an experienced radio operator—skills desperately needed in France. I trained in secret communications, security procedures, codes, surveillance awareness, and clandestine operations. My codename would be Madeleine.

Into Occupied France

In June 1943, I was flown into France and joined the Prosper resistance network around Paris. My task was to maintain wireless communication between agents in France and headquarters in London. A wireless operator was an essential connection, but also an exceptionally vulnerable one. German forces could use radio direction-finding equipment to hunt unauthorized transmissions. I therefore had to transmit quickly, change locations, conceal my equipment, and avoid patterns that might reveal where I was operating.

The Network Collapses

Soon after my arrival, disaster struck. German counterintelligence penetrated the Prosper network, and agents were arrested across the region. London offered me the opportunity to return to Britain. I chose to remain. With so many wireless operators captured, communications between Paris and London were in danger of disappearing. For a period, I became one of the most important remaining radio links between the resistance around Paris and SOE headquarters. Every transmission carried the possibility that German detection teams were drawing closer.

A Radio in a Suitcase

I moved from place to place carrying my transmitter, often relying upon safe houses and people willing to risk their own lives to shelter me. Messages had to be encoded, transmitted, received, and decoded while avoiding surveillance. I changed my appearance and locations and continued operating while German authorities searched for me. Courage in such circumstances did not mean feeling no fear. It meant completing the next message while understanding perfectly well what might happen if someone came through the door.

Betrayed and Captured

In October 1943, I was betrayed and arrested by the Sicherheitsdienst, the German security service. I attempted to escape almost immediately and later tried again with other prisoners. After the second attempt, I was classified as an especially dangerous prisoner and transported to Germany. I was held in chains for long periods and repeatedly questioned. My captors wanted intelligence about British operations and other agents. I refused to cooperate. Even captivity did not release an agent from the responsibility to protect others.

Spies Behind Enemy Lines: Resistance Networks and Secret Radios - Told by Khan

In occupied France, you learned quickly that an ordinary street could contain several different wars at once. German soldiers might be standing at a railway station. A French policeman might be checking papers. A woman carrying groceries might secretly be delivering a message to the Resistance. And somewhere behind the shutters of an apartment, a wireless operator might be tapping out coded words to London while German technicians searched the airwaves for the signal. In 1943, I became one of those operators.

Entering Occupied France

I had joined Britain's Special Operations Executive, the SOE, and was trained as a wireless operator. Because I had grown up in France and spoke French fluently, I could move through French society more naturally than many British agents. In June 1943, I was flown into France under the codename Madeleine and sent to work with the Prosper network in the Paris region. My radio was my connection to Britain. Through it, resistance networks could request supplies, report developments, and communicate with SOE headquarters. Without wireless communication, agents scattered across occupied Europe could become dangerously isolated.

The Resistance Was a Network of People

People often speak of "the French Resistance" as though it were one organization. It was actually composed of many groups and networks with different leaders, political beliefs, methods, and connections. Some collected intelligence. Others distributed underground newspapers, hid escaped prisoners and Allied airmen, sabotaged transportation, or prepared for future Allied operations. SOE sought to support resistance groups with agents, weapons, money, training, and communications. Every person involved created another link in the network—but every additional link also created another opportunity for discovery.

My Radio Was Both Weapon and Trap

A clandestine wireless set was immensely valuable and extremely dangerous. I could encode a message and transmit it to Britain using Morse code, but German forces were searching for unauthorized radio signals. Direction-finding equipment could help narrow down where a transmitter was operating. That meant I could not simply sit comfortably in one room transmitting for hours. Operators needed to send messages efficiently, move between locations, conceal equipment, and remain alert for surveillance. Every additional minute on the air increased the danger.

The Network Begins to Collapse

Not long after I arrived, German counterintelligence struck heavily against the Prosper network. Arrests spread through the organization, and many agents disappeared into German custody. Headquarters offered me the opportunity to return to Britain because the situation had become so dangerous. I chose to remain. With wireless operators being captured, London's communications with agents around Paris were being badly damaged. For a time, I became one of SOE's few remaining wireless links in the area. The work became lonelier, and every familiar address could suddenly become unsafe.

Living Beneath an Occupation

Operating secretly was not a matter of wearing a clever disguise and slipping dramatically through shadows. It meant controlling ordinary details. Identity papers had to withstand inspection. Names and explanations had to remain consistent. Meetings had to be arranged without attracting attention. Safe houses could become compromised. Neighbors might notice unfamiliar visitors. German security forces and French collaborators could watch railway stations, apartments, cafés, and streets. The safest-looking routine could become dangerous if repeated too often.

When One Agent Was Captured

The greatest danger to an intelligence network was often not a broken code but a captured person. An arrested agent might possess addresses, names, documents, or knowledge of meeting places. German security services could also seize radios and attempt to continue transmissions while pretending that the original operator remained free. This made security checks within coded messages extremely important. A compromised wireless link could become a doorway through which the enemy reached an entire network. Trust was necessary, but in clandestine work it could never be careless.

The Dangerous Life of a Secret Agent: Surveillance, Capture, Etc - Told by Khan

A secret agent does not know when she has been discovered. That is what makes surveillance so frightening. If soldiers are running toward you, the danger is obvious. In occupied Paris, danger might be the same man appearing twice on the Métro, a stranger watching an apartment entrance, or a friend who suddenly fails to arrive for a meeting. When I worked for Britain's Special Operations Executive in France in 1943, survival depended upon noticing such details before German counterintelligence connected them to me.

The Hunters Were Hunting Us

German security organizations devoted considerable effort to finding resistance members and Allied agents. The Sicherheitsdienst, or SD, and Gestapo pursued clandestine networks through informants, surveillance, interrogations, captured records, and searches. Radio operators faced an additional threat because German specialists could detect unauthorized transmissions and use direction finding to help locate their source. My wireless set connected me with London, but each transmission also announced that somewhere in the city an illegal transmitter was operating. Intelligence was therefore a contest between two groups studying each other's habits.

Never Become Predictable

We were trained to make surveillance difficult. An agent might change routes, avoid unnecessary routines, use false identities, arrange secret meetings, and move communications equipment between locations. One had to remember names, cover stories, addresses, passwords, and security procedures while appearing perfectly ordinary. A person who looked frightened at every checkpoint would attract attention. Yet appearing too confident could be dangerous as well. The object was not to look like a spy. The object was to become someone whom nobody remembered seeing.

When a Network Breaks

The capture of one agent could endanger dozens of others. A prisoner might know safe-house addresses, meeting locations, names, or communication procedures. Documents found during a search could provide additional clues. A captured radio was especially dangerous because German operators sometimes attempted what the British called a wireless game, transmitting messages through seized sets while pretending the original agent was still operating freely. Proper security checks in transmissions were supposed to help London determine whether an operator was actually sending under enemy control.

Paris Becomes More Dangerous

Soon after I arrived in France, the Prosper network with which I was associated suffered devastating arrests. Many agents were captured, and SOE offered to bring me home. I refused because wireless communications between Paris and London had become desperately important. I changed locations and continued transmitting. I also altered my appearance, including dyeing my hair, as the search for me intensified. Remaining in France was dangerous, but leaving would have meant removing one of the few remaining wireless connections between London and agents around Paris.

Betrayal

In October 1943, my luck ended. I was betrayed to the Germans and arrested in Paris. Accounts of the betrayal have produced disagreements over particular details, but I was taken to the SD headquarters at 84 Avenue Foch. I resisted captivity almost immediately. During my detention, I attempted escape, including an effort with fellow prisoners from the building's roof. After another escape attempt, German authorities classified me as highly dangerous and sent me to Germany rather than keeping me in France.

The Prisoner's Final Secret

Capture did not end the intelligence battle. Prisoners could still protect information by refusing to cooperate, while interrogators attempted to obtain names, locations, procedures, and organizational details. I was imprisoned at Pforzheim in Germany, where I was kept under harsh conditions, often shackled and isolated. I did not provide my captors with the cooperation they wanted. In September 1944, I was transferred with three other female SOE agents to Dachau concentration camp, where we were executed.

The Cost of the Secret War

There is a temptation to make espionage sound romantic: secret identities, hidden radios, coded messages, and narrow escapes. Those things were real, but so were betrayal, imprisonment, torture, and death. I do not apologize for choosing to resist Nazi occupation, but I would not disguise the price paid by those who entered that hidden war. Counterintelligence taught us that the smallest mistake could become a chain leading from one person to another. Courage mattered, but courage alone was not enough. A successful agent needed discipline, caution, memory, judgment—and the understanding that protecting one secret might protect many lives.

Operation Fortitude: The Intelligence Deception Behind D-Day - Told by García

By 1944, we faced an interesting problem: we had to conceal something that could not possibly be hidden. Germany knew the Allies intended to invade Western Europe. Hundreds of thousands of troops were assembling in Britain, ships crowded the harbors, and aircraft filled the skies. We could not persuade the Germans that there would be no invasion. Instead, we needed them to remain uncertain about where the main attack would fall. My contribution was simple in principle and extraordinarily complicated in practice: I would help convince German intelligence that what they expected to see was actually true.

The Great Question: Where?

The shortest route across the English Channel led toward the Pas-de-Calais, while the Allies were secretly preparing to land in Normandy. German planners had good reasons to worry about Calais. It was close to Britain and strategically important. The Allied deception plan known as Operation Fortitude was part of the larger Operation Bodyguard and was designed to reinforce German uncertainty about Allied intentions. Fortitude North suggested a threat against Norway, while Fortitude South helped create the impression that a major force was preparing to strike the Pas-de-Calais.

An Army That Wasn't Coming

One of the most famous elements of Fortitude South was the First U.S. Army Group, or FUSAG. It was a real formation on paper, but the enormous invasion force the Germans were encouraged to imagine was largely fictitious. General George S. Patton was associated with it, which made the story more convincing because the Germans regarded him as an important Allied commander. False radio traffic and controlled information helped create the impression of military preparations in southeastern England. Physical deception also contributed to the broader illusion, although the popular image of vast fields of inflatable tanks explains only a small portion of a much more sophisticated operation.

My Imaginary Army of Spies

This was where GARBO entered the story. By then, German intelligence believed I controlled a network of subagents throughout Britain. They did not know that my supposed informants were largely inventions created by British intelligence and me. These fictional people could report troop movements, military preparations, conversations, and observations from different parts of Britain. Because I had spent years building their identities and establishing my credibility, the Germans had reasons to take their reports seriously. A lie created yesterday is suspicious. A source trusted for years is considerably more useful.

Truth Was Part of the Deception

We could not simply invent everything. Successful deception depends upon a carefully controlled mixture of truth, delay, ambiguity, and falsehood. Before D-Day, I even sent information warning that an attack toward Normandy was approaching, but the message was deliberately arranged so that German intelligence received it too late to provide useful warning. This helped protect my credibility. I could later argue that I had warned them. If they had failed to act quickly enough, that was hardly the fault of their faithful agent Arabel.

June 6, 1944

Then the invasion began. On June 6, Allied forces landed in Normandy. At that point, one might imagine the deception was finished. In fact, one of its most important phases had just begun. We wanted German commanders to believe Normandy might be a diversion preceding a larger attack against the Pas-de-Calais. My network continued sending reports supporting that possibility. The existence of FUSAG and other deceptive indicators helped reinforce the idea that substantial Allied forces remained available for another assault.

Keeping German Forces Waiting

German decisions after D-Day resulted from many factors, including Hitler's own expectations, German intelligence assessments, the military situation, and Allied deception efforts. Fortitude did not single-handedly freeze every German unit in place. Nevertheless, the deception helped sustain German concern about the Pas-de-Calais, contributing to the retention of important forces there after the Normandy landings had begun. Every day German commanders remained uncertain about whether another major invasion was coming gave Allied forces in Normandy valuable time to strengthen their position.

Decorated by the Enemy

The strangest proof of my success came from Germany itself. German intelligence continued to trust me so thoroughly that I was awarded the Iron Cross in 1944 for my supposed service to the German war effort. Britain later appointed me a Member of the Order of the British Empire. I had managed to receive decorations from opposing sides while serving only one of them. The irony was not lost on me.

The Battlefield Inside the Mind

Operation Fortitude demonstrates something important about warfare: sometimes the objective is not to hide reality but to surround reality with several believable possibilities. The Germans knew an invasion was coming. They simply needed to remain uncertain about which invasion was the decisive one. Tanks, aircraft, ships, resistance fighters, and soldiers made D-Day possible, and they bore the terrible danger of the actual battle. People such as myself fought somewhere less visible—inside the enemy's understanding of events. If you can influence what an opponent believes, you may influence where he sends his armies before your own soldiers ever meet them.

From Secret Information to Victory: Intelligence Analysis and the Legacy of WWII Espionage - Told by García, Donovan, Turing, and Khan

Imagine the four of us seated around the same table after examining the secret war we fought in very different ways. One of us created imaginary spies, another organized an American intelligence service, another attacked encrypted communications with mathematics, and another carried a wireless radio through occupied France. Our experiences reveal an important truth about World War II: information alone did not win battles. Someone had to collect it, protect it, analyze it, decide whether to trust it, and deliver it to people who could act upon it.

What Good Is a Secret?

William J. Donovan: "I would begin with a lawyer's question: what can you prove? During the war, intelligence reached us from agents, resistance groups, aerial photographs, captured documents, intercepted communications, newspapers, diplomats, and military units. One report might say German troops were moving east while another suggested they were preparing to move west. The task of intelligence analysis was to compare sources and determine what the evidence actually supported. The OSS therefore employed not only spies but historians, economists, geographers, lawyers, linguists, and other specialists. A secret locked in a filing cabinet accomplishes nothing. Intelligence becomes valuable when it helps someone make a better decision."

Alan Turing: "And one should not confuse deciphering a message with understanding it. At Bletchley Park, breaking encrypted German communications could produce an extraordinary quantity of information. But suppose you decrypt a message mentioning submarines, coordinates, fuel, and a particular date. You must determine who transmitted it, whether the information is current, how it relates to other messages, and whether acting upon it might reveal that you are reading the enemy's communications. Cryptanalysis solved one mathematical problem and immediately created several strategic ones. Rather inconveniently, solving one puzzle tends to produce another."

The Human Network

Noor Inayat Khan: "From occupied France, the problem looked different. Information had to reach London before anyone could analyze it. Resistance members gathered reports, couriers carried messages, and wireless operators such as myself transmitted coded information while German forces attempted to locate us. A headquarters might eventually receive a neat sheet of intelligence, but behind those words could be many people who had risked arrest simply to collect and transmit them. Intelligence organizations depended upon human networks, and the capture of one person could threaten many others."

Juan Pujol García: "And then there was the amusing possibility that the information was deliberately false. I spent years persuading German intelligence to trust reports from an imaginary network of agents. During the deception surrounding D-Day, that trust became extremely useful. This demonstrates why analysts could never ask merely, 'What does our source report?' They also had to ask, 'Why should we believe him?' An intelligence service that collects enormous quantities of information without judging reliability may simply become very efficiently misinformed."

When Intelligence Reached the Battlefield

Donovan: "That is why intelligence had to be combined. Human agents might report troop movements. Signals intelligence could reveal communications patterns. Aerial reconnaissance might photograph installations. Economic analysts could examine whether enemy industries could replace lost equipment. None of these sources was perfect by itself. Together they could provide commanders with a stronger picture. Intelligence did not replace soldiers, sailors, or airmen, nor did it guarantee victory. It reduced uncertainty—and in war, reducing uncertainty can save lives."

Turing: "Timing was equally important. If we discovered the position of a U-boat after a convoy had already sailed through the area, the information might be historically interesting but militarily useless. Intelligence therefore became a race between discovery and expiration. Machines helped us process problems more rapidly, but human judgment remained essential. The wartime need to process enormous quantities of information also accelerated developments in cryptanalysis, electronics, and computing that would continue long after the war."

The Secret War Continues

Pujol García: "When Germany surrendered in 1945, the techniques of deception did not disappear. Governments had learned how effectively double agents, controlled information, and carefully constructed false narratives could influence an opponent. The coming Cold War would provide ample employment for such ideas. Espionage would increasingly become a contest fought through intelligence networks, defectors, covert operations, surveillance, and deception rather than armies meeting openly on the same battlefield."

Donovan: "The institutions changed as well. The OSS was dissolved in 1945, but I argued that the United States still needed a permanent centralized foreign intelligence capability. In 1947, Congress created the Central Intelligence Agency under the National Security Act. Britain retained its established intelligence organizations, while the Soviet Union and other nations expanded their own services. World War II had demonstrated that intelligence could no longer be treated merely as something improvised when a war began."

What the Secret War Left Behind

Noor Inayat Khan: "But institutions should never make us forget the people. Intelligence work could demand extraordinary sacrifice from agents, radio operators, resistance members, analysts, and civilians who sheltered them. Many did not survive to see what their information accomplished. The secret war was secret partly because those who fought it often received little public recognition at the time."

Turing: "Perhaps that is the final lesson. Intelligence did not win World War II by itself, and it would be poor history to claim that it did. Industrial production, military leadership, resistance, geography, logistics, technology, diplomacy, and millions of service members all mattered. Intelligence provided something different: knowledge. Our generation demonstrated how mathematics, human observation, technology, deception, and analysis could transform scattered fragments into decisions. After 1945, governments would never look at information quite the same way again. The secret battlefield had become a permanent part of modern warfare."