# 1912 - 1954

Alan Turing is regarded as the founder of computer science. He was a mathematician, philosopher and computer pioneer. He was recruited from Cambridge University, where he studied mathematics, to Bletchley Park for code-breaking activities at the start of World War 2. He published a landmark paper in 1936 which includes a description of what has become known as the Universal Turing Machine (UTM). This is not a physical device but a logical device – a thought experiment that logically describes the essential principle of general purpose computation. The UTM was the first contribution to a formal theory of computation. In his 1936 paper Turing used it to solve a difficult problem in mathematical logic that had baffled mathematicians for a long time. Its practical significance was not evident at the time.

At Bletchley Park, at the Government Code and Cypher School, Turing's advanced mathematical knowledge was put to good use in his code-breaking activities. He helped to crack the German naval cypher codes used on Enigma machines that sent coded messages to German U-boat submarines.

Turing played a major role in the design of an electromechanical machine called the 'Bombe' to help break the Enigma cypher. This work ran in parallel with the work on Colossus that was also being built at Bletchley Park to break the German Lorenz military code. Turing did not work directly on Colossus but he did devise a manual technique called Turingery or Turing's Method, that helped work out some of the settings on the Lorenz coding machine.

After World War 2. Turing went to work at the National Physical Laboratory (NPL) in Teddington (South West London), where he worked on ideas for an Automatic Computing Engine (ACE). He had left NPL by the time ACE was built but the final design was heavily influenced by his pioneering work there. Turing left NPL in 1948 to join a team at Manchester. He worked on an input output system for the already running Manchester 'Baby', the first experimental stored program computer built there by Freddie Williams and Tom Kilburn. He also devised a programming system for it. While in Manchester he developed highly original ideas on artificial intelligence and on artificial life. He expressed the view that there was nothing in principle that a human could do that a machine ultimately could not.

Turing died in 1954 at the age of 42 from cyanide poisoning.