Alan Turing (1912–1954) was a British scientist, cryptanalyst, logician, and mathematician. Highly influential in the development of computer science, providing a formalization of the concept of the algorithm and computation with the Turing machine, which played a significant role in the creation of the modern computer. He devised a number of techniques for interpreting German ciphers in World War II, and broke the Enigma machine’s code, saving tens of thousands of lives in the process. Turing’s homosexuality resulted in a criminal prosecution in 1952–homosexual acts were illegal in the United Kingdom at the time. He was chemically castrated as an alternative to prison. He is said to have committed suicide by eating cyanide in an apple. In 2009, British Prime Minister Gordon Brown made an official public apology on behalf of the British government for the way in which Turing was mistreated after the war, a left-handed “thank you” for all the good work he had done for his country. The partially bitten apple on Steve Jobs’ computers is a silent tribute to his advances in computer science. SF Bay Times Article
Find his plaque on the southeast side of Castro St between 18th and 19th