The notable figure who was a pioneer in the field of computer science is Alan Turing. Known for his foundational work on algorithm theory and computation, Turing developed the concept of the Turing Machine, which is fundamental to modern computing. His contributions during World War II, particularly in breaking the Enigma code, showcased his brilliant analytical skills and had profound implications for the war effort. Despite facing persecution due to his sexuality, Turing's legacy endures, highlighting his crucial role in the development of theoretical computer science and artificial intelligence.