The revelations of Stephen Budiansky's dramatic history include how Britain tried to manipulate the American codebreakers and monopolize German Enigma code communications; the first detailed published explanations of how the Japanese codes were broken; and how the American codebreaking machines worked to crack the Japanese, the German, and even the Russian diplomatic codes. The compelling narrative shows the crucial effect codebreaking had on the battlefields by explaining the urgency of stopping the wolf pack U-boat attacks in the North Atlantic, the importance of halting Rommel's tanks in North Africa, and the necessity of ensuring that the Germans believed the Allies' audacious deception and cover plans for D-Day. Unveiled for the first time, the complete story of codebreaking in World War II has now been told.

Nature

The story of cryptography in the Second World War is one of the great scientific tales of the twentieth century. Budiansky has succeeded in telling it with enthusiasm and insight, delivering a book with style and substance.

List of Maps

Prologue: Midway

1. "No Good, Not Even for Intelligence"

The end of the Black Chamber / William F. Friedman picks up the pieces / "I had the good sense to get out of it!" / Room 40 / Winston Churchill, an early convert / The Foreign Office, a late convert / The Soviet intercepts / A strategic failure for intelligence

2. Nature of the Beast

The birth of codebreaking / Machine ciphers, Poland, and the Enigma / Depth reading / The distinct limitations of thievery / Solving the Red machine

3. "Il y a du Nouveau"

1939, a dark new year / Meeting at Pyry Forest / Marian Rejewski's mathematical feat / Recovering the daily Enigma keys / Alan Turing and other "men of the professor type" / Bletchley Park / The Poles' flight

4. Fighting Back

British mathematicians vs. the Enigma / The bombe takes shape / "A pile of dull, disjointed, and enigmatic scraps" / Cryptanalytic talent / Norway and Yellow / France and Red / HMS Glorious

5. Impossible Problems

The sinking of U-33 / Naval Enigma and the bombe / Operation ruthless and other straws / American isolationism / Purple / The British charm offensive / A mission to Bletchley, bearing gifts

6. Success Breeds Success

The Blitz / Cape Matapan / Boniface, barbarossa, and Bismarck / Naval Enigma, U-110, and the trawler pinches / The eastern front and German atrocities / Trafalgar Day / Cribs and continuity

7. The Machines

The British make polite noises / IBM machines and JN-25 / The machine attack on Floradora / Washington at war / Military vs. civilians / An American ultimatum / Better bombes / High-speed analyzers

8. Paranoia Is Our Profession

Dönitz's suspicions / The evacuation of Corregidor / The Midway leak / Some bungled operations / "do not talk at meals" / Suspicions among friends

9. The Shadow War

Calling the shots in the Mediterranean / torch and deception / The flight from Vichy / Atlantic convoys / U-559 and the breaking of Shark / The hunt for leaks / The American invasion / Pressures and diversions / Women in uniform

10. Command of the Ether

Russian espionage and Project venona / GEE and Fish / Masters of deception / Yamamoto / The Water Transport code / Failure in the Ardennes / Signaling the end

Epilogue: Legacy

Appendixes

A. Chronology

B. Naval Enigma: Its Indicating System and the Method of "Banburismus"

C. Cryptanalysis of the Purple Machine

D. The Intercept Network

E. Rapid Analytical Machinery (RAM)

Notes

Glossary and Abbreviations

Bibliography

Acknowledgments

Index