Alan Mathison Turing, b. June 23, 1912, d. June 7, 1954. He played a significant rôle in cracking German codes during World War II, and proposed a test for machine intelligence. He went to King’s College, Cambridge in 1931 to read Mathematics. Alan Turing graduated in 1934, and was a fellow at Kings for two years, during which he wrote his now famous paper published in 1937, On Computable Numbers, with an Application to the Entscheidungsproblem. In it, he proposed a machine that could move from one state to another by following a rigorous set of rules. From this he was able to show the existence of uncomputable functions. For example, no program can determine if any arbitrary program will terminate. This led to a computing scheme that foreshadowed the logic of digital computers. He also proposed a test for machine intelligence, and investigated the first few zeros of the Riemann zeta function.