The extraordinary wartime exploits of the British codebreakers based at Bletchley Park continue to fascinate and amaze. In The Emperor's Codes Michael Smith tells the story of how Japan's wartime codes were broken, and the consequences for the Second World War. He describes how the Japanese ciphers were broken and the effect on the lives of the codebreakers themselves. Using material from recently declassified British files, privileged access to Australian secret official histories and interviews with British, American and Australian codebreakers, this is the first full account of the critical role played by Bletchley Park and its main outposts around the world.