Photographer Unknown, Alan Turing at Bosham, 1939
This image shows mathematician and computer pioneer Alan Turing at Bosham, a coastal village and civil parish in Chichester, England.. He is seated with several figures including two Jewish refugee boys he rescued from Nazi Germany.
Alan Turing’s central contribution to science and philosophy came through his treating the subject of symbolic logic as a new branch of applied mathematics, giving it a physical and engineering content. Though a shy man, he had a pivotal role in world history through his role in Second World War cryptology. From 1939 to 1945 Turing was almost totally engaged in the mastery of the German enciphering machine, Enigma, and other cryptological investigations at now-famous Bletchley Park, 
the British government’s wartime communications headquarters. Turing made a unique logical contribution to the decryption of the Enigma and became the chief scientific figure, with a particular responsibility for reading the U-boat communications.
In 1948 Alan Turing moved to Manchester University, where he partly fulfilled the expectations placed upon him to plan software for the pioneer computer development there, but still remained a free-ranging thinker. It was here that his famous 1950 paper, “Computing Machinery and Intelligence,” was written. In 1951 Turing was elected a Fellow of the Royal Society for his 1936 achievement, yet at the same time he was striking into entirely new territory with a mathematical theory of biological morphogenesis.
This work was interrupted by Alan Turing’s arrest in February 1952 for his sexual affair with a young Manchester man, and he was obliged, to escape imprisonment, to undergo the injection of oestrogen intended to negate his sexual drive. He was disqualified from continuing secret cryptological work. Turing’s general libertarian attitude was enhanced rather than suppressed by the criminal trial, and his intellectual individuality also 
remained as lively as ever. While remaining formally a Reader in the Theory of Computing, he not only embarked on more ambitious applications of his biological theory, but advanced new ideas for fundamental physics.
For this reason Alan Turing’s death, on 7 June 1954, at his home in Wilmslow, Cheshire, came as a general surprise. In hindsight it is obvious that Turing’s unique status in Anglo-American secret communication work meant that there were pressures on him of which his contemporaries were unaware. Turing had previously spoken of suicide; and his death by cyanide poisoning was most likely by his own hand. The symbolism of his death’s dramatic element—a partly eaten apple—has continued to haunt the intellectual Eden from which Alan Turing was expelled.
In 1967, the British government took its first steps toward decriminalizing homosexuality. It was not until 2009 that the government officially apologized for its treatment of Alan Turing and thousand of other gay men who were convicted under the existing Victorian laws. In 2013, Queen Elizabeth II granted Alan Turing a royal pardon, 59 years after a housekeeper found his body at his home at Wilmslow, near Manchester, in northwest England.