Kahn, David. The Codebreakers: The Comprehensive History of Secret Communication from Ancient Times to the Internet. New York: Scribner, 1996. 1,181pp. $65
David Kahn's massive book is fascinating and absorbing. He covers the full spectrum of ciphers and encryption, as well as methods of uncovering the meaning of such coded messages. Kahn addresses not only their use by governments to support diplomatic and military activities but also their use by businesses, by criminal organizations, for personal communications, and in espionage. He even shows the similarities between the processes employed in cryptanalysis and those used by historians and archeologists to discover the meaning of ancient languages. An editor for Newsday with a Ph.D. from Oxford in modem history, Kahn has been visiting historian at the National Security Agency and has been aptly described as the world's leading expert on the history of cryptology. It should be noted that this book is an updated and revised edition of a 1967 publication that Kahn intended to be the definitive history of cryptology.
The Codebreakers is filled with stories about approaches to concealing the meanings of messages and efforts to discover the meanings of the messages. Some of the stories are well known, such as how America's "Black Chamber" allowed the United States government to know in advance the Japanese negotiating position during the 1921 Washington conference on naval armaments, and to shape its own negotiating strategy accordingly. Of course, that was before Secretary of State Henry Stimson declared that "Gentlemen do not read each other's mail" and scuttled the Black Chamber in 1929 by eliminating its funding. Perhaps even better known is the role of the ENIGMA machine in World War II. Even in the best known stories, however, Kahn provides additional information and insight. For example, I found the stories of the invention of the ENIGMA machine and of Scherbius's early efforts to market it intriguing. I had not known about them before.
Many of the stories are not as famous, but they, as well as the better known ones, seem to have been carefully selected to allow an appreciation of the many factors involved in secret and hidden communications and, more importantly, to give a broad perspective on the way such communications and their compromise impact human affairs. Mature and balanced understanding is very important for those who hold positions of leadership in politics, the military, or business. This kind of understanding should help to prevent acts of gross stupidity, such as Stimson's significant reduction of America's ability to read diplomatic messages of other nations. …