Alan Turing, an English mathematician who was a trailblazer in computer theory, was born on this day in 1912. Turing is best known for a classic paper he published in 1936, "On Computable Numbers, with an Application to the Entscheidungs Problem," in which he addressed the question of whether all mathematical problems could in principle be solved. He answered no, but added a footnote describing a theoretical automatic machine that could solve any problem provided it was given the needed algorithms and instructions. Turing's machine, as it came to be known, was the first published description of a computer.

ANDREW HODGES [2]

During World War II, Turing served as a code breaker for British Intelligence. In 1950, he published a key paper describing a way to test whether a machine possessed intelligence--the Turing Test--in which an interrogator would ask questions of a remote computer or person via a keyboard. If the interrogator could not identify the computer as inhuman in a statistically significant number of cases, then artificial intelligence had been achieved, he suggested. Turing died in 1954 of cyanide poisoning, apparently a suicide.

[Source: Emily McMurray, Ed., *Notable Twentieth Century Scientists* (Gale Research Inc., ITP, 1995).]