Alan Turing was born on June 23, 1912, in London. After studying at King's College, Cambridge, and becoming a fellow at the age of 22, he did some of his most important conceptual work in inventing what he called the "a-machine," better known to the world as the Turing machine (pictured below). This hypothetical device -- which reads symbols from a paper strip of theoretically infinite length and interprets them according to an inbuilt table of rules -- is crucially important to the development of computational theory.

The work for which Turing is probably best known to the public, however, is his central role in cracking German military codes during World War II.

Turing's earlier research stood him in good stead at the ultra-secret Government Code and Cipher School, located at Bletchley Park. Along with contributing enormously to the war effort by providing detailed intelligence on German communications, his work at GCCS presaged the development of the rudimentary computers he would design after hostilities ended.

While he had already created a digital multiplier during a spell at Princeton University before the war, the design of the Automated Computing Engine, or ACE (pictured below), was to have far greater effects on the development of the computer -- providing a basis for a whole generation of devices, including the Bendix G-15.

"The very first machine that I ever got to really program was called a Bendix G-15 computer," recalls Cerf.