Alan Turing was a brilliant Cambridge mathematician who has been described as the father of the modern computer. He masterminded the cracking of the German Enigma code and was caught up in the secrecy and bureaucracy of World War II and afterwards - continually frustrated in his desire to build a machine which could think, as those with power over him feared both his homosexuality and indiscretion. This is an account of his life, which ended by his own hand.