At age 24, he wrote a paper defining one of this century's most important concepts, now called the Turing Machine; the theoretical basis for all modern computers.

A secret hero of World War Two, his wartime work remained a military secret until 1979. More than any other single person, his work led directly to Germany's defeat.

In 1945 he designed the world's first electronic, stored-program, digital computer, building upon his wartime work, and wrote papers foreseeing future decades of computer development.

By 1950 he was pursuing machine intelligence, and in a brilliant and witty paper defined what is now called the Turing Test for intelligence, which remains basic to artificial intelligence today. He devoted his last years to finding a mathematical basis for morphogenesis, the beginnings of life; his work in this area still considered pioneering.

M ost amazing of all is that he was openly homosexual. Naively honest, his personal integrity worked against him: personally shunned and professionally undermined for his disregard of convention (as a classic "absent-minded professor", and a homosexual), he lacked ambition to promote his ideas, and was finally prosecuted in Cold War England for "gross indecency", for his affair with another man. At age 42, he took his own life.

T uring may now get the attention he deserves; in his substantial biography, ALAN TURING: THE ENIGMA, Andrew Hodges, (a British homosexual mathematician himself) has brought Turing back to life in fantastically researched detail, and has spawned, amongst other things, a Broadway play (BREAKING THE CODE), and recently, appeared as a fictional character in Neal Stephenson's novel CRYPTONOMICRON.