Alan Turing was a British mathematician, computer scientist, logician, cryptanalyst, philosopher, and theoretical biologist. He is widely considered to be one of the most influential mathematicians of the 20th century and is known for his pioneering work in the field of artificial intelligence. He is also credited with cracking the German Enigma code during World War II, which helped the Allies win the war. Turing's work on the foundations of mathematics, computing, and cryptography has had a lasting impact on the world.