Mitch Leigh (born Irwin Michnick; January 30, 1928 – March 16, 2014) was an American musical theatre composer and theatrical producer best known for the musical Man of La Mancha.Leigh was born in Brooklyn, New York as Irwin Michnick. He graduated from Yale in 1951 with a Bachelor of Music, and in 1952 received his Master of Music under Paul Hindemith.He began his career as a jazz musician, and writing commercials for radio and television. In 1955 the little-known LP recording of Jean Shepherd Into the Unknown with Jazz Music was produced with Leigh writing the music for the jazz interludes between radio broadcaster Jean Shepherd's improvisations.