In the photographs, dressed in jacket and dark tie, he looks like the prefect at my grammar school who cowered against the corridor walls when other pupils approached him. The mathematician and visionary Alan Turing is the subject of a compact exhibition at the Science Museum in London.
During the Second World War Turing famously helped to crack the German Enigma code using one of the earliest electronic computers, the 'bombe'. The cracking of the cipher, which the Germans believed impossible, probably shortened the war by years, saving countless lives.
Dozens of wheels rotated in each bombe making a noise like 'a thousand knitting needles'. And a legion of bombes supported decryption on an industrial scale. So effective was it that on one occasion a message was decoded in less than 15 minutes.
When the war ended, Turing worked on the government Advanced Computing Engine (ACE) project. Before such machines were invented, large scale arithmetical calculations were carried out by teams of specially trained women.
Computers were then quickly applied to complex problems in chemistry and life sciences. At Manchester University, Turing researched the relationship between mathematics and cell growth, beginning a new field he named Morphogenesis. At Oxford, in 1957, Dorothy Hodgkin used Pilot ACE and X-ray crystallography (a technique also fundamental to the discovery of the structure of DNA) to help her to crack the structure of vitamin B12 and was awarded a Nobel Prize.
Turing was condemned for homosexuality in an era when it was illegal. Under constant surveillance as a security risk, he apparently took a bite from a cyanide-laced apple. His death was officially declared suicide, though the exact circumstances remain a mystery.
As a leader in computation--particularly in programming--he deserved better. However, in recent decades he has been recognised as one of the greatest thinkers of the 20th Century.