Alan Turing: June 23, 1914 - June 7, 1954

Alan Mathison Turing, OBE, FRS (23 June 1912 – 7 June 1954) was a British mathematician, logician, cryptanalyst, philosopher, computer scientist, mathematical biologist, and marathon and ultra distance runner. He was highly influential in the development ofcomputer science, providing a formalisation of the concepts of "algorithm" and "computation" with theTuring machine, which can be considered a model of a general purpose computer. Turing is widely considered as the "Father of Theoretical Computer Science andArtificial Intelligence.

More here http://en.m.wikipedia.org/wiki/Alan_Turing