As a 20th-century mathematician, Alan Turing left an indelible mark on the field of computer science. In his 20s, he proposed the "Turing Machine," a thought experiment about how a universal multitask computer could work, a concept which forms the basis for computers today. During World War II, Turing worked as a code breaker for Britain, and helped break the code used by the Nazis, creating a tactical advantage for the Allies. This book invites readers to explore mathematics, computing, artificial intelligence, and codebreaking; and to remember the life of a great mathematician and computer scientist.