Turing spent the rest of his short life working in the logic/mathematics field. After receiving his Ph.D. in 1938 from Princeton University (New Jersey) he returned to England and during World War II he worked in the Government Code and Cypher School where he contributed to the decoding of the German Enigma codes. After the war he helped construct the Automatic Computing Engine (ACE) in 1945. In 1948 as deputy director of the Computing Laboratory at the University of Manchester (England), Turing had access to the MADAM (Manchester Automatic Digital Machine) computer which, at the time, had the largest memory capacity in the world.

Turing's work has directly inspired the artificial intelligence wing of computer science. He believed that it was possible to build computers capable of human thought and the "Turing Test" has been used to examine this potential of computers. Basically, the test goes like this: if you are sitting at a computer terminal and "talking" with a computer and you cannot tell whether it is a human or a machine you are talking to, then the machine should be considered intelligent.

According to the Encyclopedia Brittanica (which has the incorrect date of publicaton for the paper cited above), Turing apparently committed suicide, June 7, 1954, "probably because of the depressing medical treatment that he had been forced to undergo (in lieu of prison) to 'cure' him of homosexuality". A half-eaten apple, laced with cyanide was found next to the body.