Alan Turing
A mathematician whose 1936 paper described an abstract machine from which the notion of computability and the whole theory of algorithms grew. During the war he worked at Bletchley Park on German ciphers: his bombe broke Enigma and, by later estimates, shortened the war by years. Afterwards he worked on the first computing machines and on morphogenesis, and proposed the test now called by his name. In 1952 he was convicted of homosexuality, subjected to enforced hormone treatment, and died two years later of cyanide poisoning.
Born in London on 23 June 1912 at 02:15 GMT: Britain had not yet introduced summer time, which came in 1916. The hour is taken from the birth record and is given in the biographies without variation.