In Enigma: The Battle for the Code, Hugh Sebag-Montefiore tells the secret history of World War II -- the remarkable struggle of Allied cryptanalysts to break the secret "Enigma" code employed by the mighty German military machine. The story begins in 1931 with Hans Thilo Schmidt's money problems. Many Germans were having similar difficulties at that time, but Schmidt came up with a unique solution. Using his officer brother's connections, he got a job in the government bureau that guarded the secret German military code. Smart and well educated, Schmidt had a penchant for the company of women other than his wife, felt like the world owed him a living, and had no qualms about trading government secrets for money. One he gained access to the codebooks that contained the setting for the Enigma machine, which was designed to transmit undecipherable secret messages, Schmidt was quickly able to pique the interest of the French intelligence service.
Once the French had purchased Schmidt's information, they realized that they still didn't have enough to read the Germans' secret messages. While maintaining contact with Schmidt, they made some inquiries among the British and the Poles to find out what these allies might know about Enigma. The British were keen to learn more, while the Poles secretly had a head start in breaking the code. With the outbreak of World War II and the German invasion of Poland in 1939, the Polish cryptanalysts sought refuge in France. As it became apparent that France would suffer a fate similar to Poland's, the code-breaking torch was passed to Britain.
Alan Turing, a brilliant young mathematician and one of the fathers of modern computers, built on the work of the Poles to develop a "bombe" machine that could help decipher the remarkably complex Enigma settings that were used to encrypt and transmit messages. But due to the Germans' convoluted and regularly changing encoding system, Turing and his colleagues could not read the secret messages as quickly as the war effort demanded. Faced with ever-mounting U-boat attacks on their supply convoys, the Royal Navy launched a successful series of operations that enabled them to capture the essential codebooks from German warships. Though German commanders were concerned about how much the Allies might learn, their intelligence experts convinced them that it was practically impossible to break the Enigma code. As a result, Allied cryptanalysts were able to decipher German military communications for the remainder of the war, enabling the Allies to defeat Germany at least two years earlier than they otherwise would have; without this advantage, they might not have won the war at all.
There's plenty of battle action in this book, as well as a wealth of technical detail about how the encoding and decoding machines worked. Anyone interested in World War II, spies, codes, or computers -- or who enjoys reading about the eccentricities of British intellectuals -- will find Enigma fascinating and exciting. With access to many newly declassified sources, Sebag-Montefiore has produced the first comprehensive -- and, most likely, the definitive -- study of the Enigma phenomenon.
William T. Wells lives in Winston-Salem, North Carolina.