Alan Mathison Turing was an English mathematician, computer scientist, logician, cryptanalyst, philosopher, and theoretical biologist. He lived from 23 June 1912 until 7 June 1954. Turing had a significant impact on the growth of theoretical computer science by formalising the concepts of computing and algorithms using the Turing machine, which is a model for a general-purpose computer. His contributions to theoretical computer science and artificial intelligence are largely regarded as his legacy.