Herbie Hancock was already an elite composer and improviser when Miles Davis tapped him for his second great quintet in the mid-'60s. Compositions like 1962's “Watermelon Man” show the pianist's mastery of post-bop and soul-jazz styles, and the moderate tempo of Empyrean Isles—released two years later—allowed his harmonic invention to go over easy during solos. As a style scout, he had a keen vision exploring funk fusion in The Headhunters and with hip-hop textures (“Rockit”). His latter-day appearances with Thundercat and Flying Lotus underline his importance across generations.