- The Reader of Gentlemen’s Mail: Herbert O. Yardley and the Birth of American Codebreaking
It is perhaps fitting that the life of Herbert O. Yardley, an American pioneer in the secretive field of cryptology and the man who founded the United States's first permanent organization to intercept signals and break codes, has remained largely shrouded in mystery. Until now, Yardley has never had a biographer. Thanks to David Kahn, he will never need another. Just as Yardley revealed the secrets of American codebreaking in his 1931 bestseller The American Black Chamber, Kahn has laid bare the triumphs and failures of Yardley's life in this definitive biography of one of the most important figures in the history of American intelligence.
Kahn not only traces the fascinating arc of Yardley's life but also explains why it mattered. He argues that Yardley's principal contribution was to institutionalize codebreaking in the United States. As the leader of MI-8 in the War Department during World War I and of the Cipher Bureau jointly funded by the War and State Departments from 1919 to 1929, Yardley transformed cryptology from a black art into a science. In the process, he gave the United States a new source of intelligence that often provided information otherwise [End Page 262] unobtainable. Yardley's greatest triumph was the Cipher Bureau's reading of Japanese diplomatic codes during the 1921 Washington Conference on the Limitation of Armament. The decrypted telegrams revealed Japan's willingness to accept the tonnage ratio for capital ships proposed by the United States and Great Britain. Their resolve bolstered, the U.S. negotiators waited until Japan agreed to the figure they had suggested. The efforts of Yardley and his codebreakers helped their government save millions of dollars and ease tensions in the Pacific.
As one might expect from the author of The Codebreakers and a leading expert on cryptology, Kahn provides valuable insight into the process of codebreaking. He details how Yardley and his staff attacked the codes of their primary targets—Japan, Great Britain, Mexico, Germany, and the Soviet Union. Although success against British and German codes was limited and interest in Soviet codes waned, the Cipher Bureau repeatedly broke the codes of Mexico and other Latin American nations, as well as those of Japan. Even more interesting is Kahn's discussion of how codebreaking has evolved. He explains that Yardley's success was due to his administrative and management skills during an era when cryptanalysis shifted from artisanal piece work to mass production and that Yardley's career paralleled the rise of intelligence as a significant factor in international affairs.
The book is exhaustively researched; it is based on more than twenty-five interviews and material from over thirty archives in five different countries and six different languages. It is also remarkably evenhanded. Kahn examines Yardley's flaws as well as his successes. He points out that Yardley was a better executive than cryptanalyst. He also notes that Yardley's greed distracted him from taking the steps necessary to ensure the future of the Cipher Bureau, such as recruiting, training, and developing new codebreaking methods. Anyone interested in the history of codes and ciphers, intelligence, or twentieth-century international relations will find this biography of America's first official codebreaker worthwhile.