The emperor's codes : the breaking of Japan's secret ciphers by Michael Smith

"The Emperor's Codes takes the reader step-by-step through the codebreaking process, explaining exactly how the codebreakers went about their daunting task-made even more difficult by the vast linguistic differences between Japanese and English. It details the grueling work and almost unfathomable dedication demonstrated by these relatively unsung heroes, without whose extraordinary exploits the outcome of World War II might have been very different." - Editorial Reviews