Turing devised the concept of an abstract computing construct that would later come to be called the “universal Turing machine”, and was employed to solve a central mathematical problem posed by the mathematician Hilbert, known as the halting problem. Through this work a deep understanding of how all computers must work was devised, as well as the basic idea of computer algorithms. This established the principles of computability (also contributed to by Church with an alternate abstraction, the lambda calculus). Any computer that can be fully general purpose is identified as a “Turing equivalent” to this day.

Alan Turing laid the theoretic foundations of what would become the field of computer science, and in so doing defined what computability itself was. Due to his theoretical and applied research, Alan Turing is noted as one of the premier contributors to the establishment of modern computing. He applied his concepts and insights into the development of automated computing systems for breaking the German Enigma code during World War II, and developed one of the first stored-program digital electronic computers, the automatic computing engine (ACE).

Alan Turing produced the first full design of a stored-program digital electronic computer, the ACE, which for various reasons was not built until after his premature death. He conceived of a test that would mark the achievement of a thinking machine; this has come to be called the “Turing test” for machine intelligence. However, a smaller version, the Pilot ACE, was implemented and the concepts incorporated in this early work had significant impact on future computer designs. Toward the end of his life, Turing considered the implications of mechanical computing and the idea of artificial intelligence.

Turing brought his prodigious acumen and insights in mechanical computation to the requirements of crypto-analysis, and more specifically code breaking at Bletchley Park in England, where the challenge of decoding Enigma messages was a priority. His contributions to the development of advanced “bombes”, electromechanical computers that tested many possible decoding combinations, are considered critical to bringing World War II to a successful and relatively fast conclusion and saving many lives. Among other effects, it was crucial to helping win the Battle of the Atlantic, enabling supplies and personnel to cross the ocean from the United States and Canada to Great Britain.