Herbert Jeffrey Hancock (born April 12, 1940) is an American pianist, keyboardist, bandleader, composer and actor. Hancock started his career with Donald Byrd. He shortly thereafter joined the Miles Davis Quintet, where he helped to redefine the role of a jazz rhythm section and was one of the primary architects of the post-bop sound. In the 1970s, Hancock experimented with jazz fusion, funk, and electro styles.