How I Discovered World War II's Greatest Spy and Other Stories of Intelligence and Code: 1st Edition (Hardback) book cover

How I Discovered World War II's Greatest Spy and Other Stories of Intelligence and Code

1st Edition

By David Kahn

Auerbach Publications

489 pages | 40 B/W Illus.

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Hardback: 9781466561991
pub: 2014-01-17
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Spies, secret messages, and military intelligence have fascinated readers for centuries but never more than today, when terrorists threaten America and society depends so heavily on communications. Much of what was known about communications intelligence came first from David Kahn's pathbreaking book, The Codebreakers. Kahn, considered the dean of intelligence historians, is also the author of Hitler’s Spies: German Military Intelligence in World War IIand Seizing the Enigma: The Race to Break the German U-Boat Codes, 1939-1943,among other books and articles.

Kahn’s latest book,How I Discovered World War II's Greatest Spy and Other Stories of Intelligence and Code,provides insights into the dark realm of intelligence and code that will fascinate cryptologists, intelligence personnel, and the millions interested in military history, espionage, and global affairs. It opens with Kahn telling how he discovered the identity of the man who sold key information about Germany’s Enigma machine during World War II that enabled Polish and then British codebreakers to read secret messages.

Next Kahn addresses the question often asked about Pearl Harbor: since we were breaking Japan’s codes, did President Roosevelt know that Japan was going to attack and let it happen to bring a reluctant nation into the war? Kahn looks into why Nazi Germany’s totalitarian intelligence was so poor, offers a theory of intelligence, explicates what Clausewitz said about intelligence, tells—on the basis of an interview with a head of Soviet codebreaking—something about Soviet Comint in the Cold War, and reveals how the Allies suppressed the second greatest secret of WWII.

Providing an inside look into the efforts to gather and exploit intelligence during the past century, this book presents powerful ideas that can help guide present and future intelligence efforts. Though stories of WWII spying and codebreaking may seem worlds apart from social media security, computer viruses, and Internet surveillance, this book offers timeless lessons that may help today’s leaders avoid making the same mistakes that have helped bring at least one global power to its knees.

The book includes a Foreword written by Bruce Schneier.


When it comes to documenting the history of cryptography, David Kahn is singularly one of the finest, if not the finest writers in that domain. For anyone with an interest in the topic, Kahn's works are read in detail and anticipated. … For those that have read some of Kahn's other works and are looking for more, How I Discovered World War IIs Greatest Spy and Other Stories of Intelligence and Codewill be an enjoyable read.

Ben Rothke, Information Security Manager, Wyndham Worldwide Corp., writing on

How I Discovered World War II’s Greatest Spy and Other Stories of Intelligence and Codeis the latest book by the distinguished intelligence historian David Kahn. This volume is a collection of thirty articles by Kahn, all of which have been previously published in a variety of publications, but have been brought together here as they are viewed by Kahn as having enduring value to intelligence historians and complement his earlier books. … Kahn offers students of intelligence history a context and useful starting point for their work. … an interesting and worthwhile collection.

Alan MacLeod, University of Leeds, writing in the Journal of Military History, July 2014

Table of Contents


How I Discovered World War II’s Greatest Spy

Who Was the Greatest Spy of World War II?


Did Roosevelt Know?

Pearl Harbor and the Inadequacy of Cryptanalysis

Appendix: A Japanese Cryptosystem

The Woman Who Made the Key Discovery

How the United States Viewed Germany and Japan in 1941

Roosevelt, Magic, and Ultra

Edward Bell and His Zimmermann Telegram Memoranda

Cryptology and the Origins of Spread Spectrum

Secret Telephone in the Cabinet War Rooms

Defining Terms

The First Unbreakable Scrambler

Vocoder Speech Synthesizer Studied

Enter the X-System

Telephones Protected against Tapping

Training Conducted in Secret

For Churchill, a Cigar and Informality

General Strategy by Telephone

Summit Conferences Amid Informality

To Probe Further


Rise of Intelligence

Intelligence in World War II: A Survey

Germany’s Intelligence Failure in World War II

An Enigma Chronology

The Black Code

Nothing Sacred: The Allied Solution of Vatican Codes in World War II

Finland’s Codebreaking in World War II

Soviet Comint in the Cold War

How the Allies Suppressed the Second Greatest Secret of World War II


Part IV A Theory, Clausewitz, and More

An Historical Theory of Intelligence

The Past

The Present

The Future

Clausewitz on Intelligence

Surprise and Secrecy: Two Thoughts

Intelligence Lessons in Macbeth

How Garbles Tricked History

The Cryptologic Origin of Braille

The Only False Message I Know

The Prehistory of the General Staff


Charles J. Mendelsohn and why I Envy Him


The Man in the Iron Mask: Encore ET Enfin, Cryptologically

Chiffres Diplomatiques

Students Better than a Pro (Bazeries) and an Author (Candela)

The Old Master of Austrian Cryptology

Book Review


Enigma Uncracked: The Allies Fail to Break the German Cipher Machine

The Future of the Past: Questions in Cryptologic History


About the Author

David Kahn is universally regarded as the dean of intelligence historians. He is the author of Seizing the Enigma: The Race to Break the German U-Boats Codes, 1939-1943. His pathbreaking book The Codebreakers, the classic history of codemaking and codebreaking remains in stalwart print 45 years after its publication (portions have been updated). He is also the co-founder of the Taylor & Francis journal, Cryptologia, which continues to attract new subscribers.

Subject Categories

BISAC Subject Codes/Headings:
COMPUTERS / Security / General
COMPUTERS / Security / Cryptography
POLITICAL SCIENCE / Political Freedom & Security / International Security