Alan Turing
Alan Turing (1912 - 1954) was a British mathematician considered to be the founder of modern computer science and cryptography.[1]
In the 1930s Turing proposed the concept of a "Universal Turing Machine". Turing had, first, proposed that the calculations needed to calculate any formula could be broken down into a base set of instructions that could in principle be followed by a machine: the "Turing Machine". Once fully formalized the calculations needed to derive the instructions themselves were capable of being run by a Turing Machine. The looped logic allowed the conception of a Turing Machine that could create its own instruction and, in principle, run a huge variety of calculations.
During World War II Turing was assigned to the military code breaking unit at Bletchley Park. Working on the decoding of the German's "Enigma" and, later, "Ultra" codes the group came to place increasing reliance on the formalization of computational procedures. The combination of this formalization of the work they were doing and Turing's earlier concept of the "Universal Turing Machine" lead to his proposal of creating an actual, rather than theoretical, electronic "Universal Turing Machine": the first electronic computer.
In his 1950 paper "Computing Machinery and Intelligence" (Mind 49: 433-460) Turing proposed a test (apparently heavily influenced by Logical Positivism) for establishing whether a computer could think.
His arrest in 1952 for homosexuality and the subsequent withdrawal of his security clearance appears to have contributed to his suicide by cyanide poisoning in 1954.[2]
References
Online biography: http://www.turing.org.uk/bio/
Computing Machinery and Intelligence: http://cogprints.org/499/00/turing.html