The British mathematician Alan Mathison Turing (1912-1954) was noted for his contributions to mathematical logic and to the early theory, construction, and use of computers.

Alan Turing was born in London, England, on June 23, 1912. Both his parents had upper middle class origins, and his father continued that tradition as an administrator in the Indian civil service. With his father off in India, Turing was sent away to private boarding schools. After some early problems with social adjustment, he distinguished himself in mathematics and science.

Turing's exceptional mathematical abilities were first generally recognized in his college years (1931-1936) at King's College of Cambridge University. His most important mathematical work, "On Computable Numbers," was written in Cambridge in 1936. In this paper Turing answered a question of great significance to mathematical logic--namely, which functions in mathematics can be computed by an entirely mechanical procedure. His answer was phrased in terms of...