Textbook of AI

Bletchley Park was the principal centre of British signals intelligence during the Second World War, located in Buckinghamshire about 80 km northwest of London. From 1939 to 1945 it housed the Government Code and Cypher School (GC&CS) and at its peak employed over ten thousand staff working on the cryptanalysis of German, Italian and Japanese military communications.

Bletchley's most celebrated achievement was the systematic breaking of the German Enigma cipher. Alan Turing, recruited from Cambridge in September 1939, designed the electromechanical Bombe machine that mechanised the search for daily Enigma settings. By 1942 daily Enigma traffic across most German services was being read, often within hours of transmission. The breaking of the more complex Lorenz cipher used by Hitler's high command was achieved with the help of Colossus, a programmable electronic digital computer, the first of its kind , designed by Tommy Flowers at the General Post Office Research Station and operational from 1944.

Bletchley's contribution to the war effort is generally judged to have shortened the conflict by two to four years. Its contribution to AI is indirect but real: the wartime work shaped Turing's thinking on machine intelligence, and the post-war diaspora of Bletchley alumni, including Turing himself, Donald Michie, I. J. Good and Max Newman, populated the early British computing and AI communities at Manchester, the National Physical Laboratory and Edinburgh.

The site was kept secret until the 1970s. It now operates as a museum.