Thelonious Sphere Monk (October 10, 1917-February 17, 1982) was an American jazz pianist and composer who, according to The Penguin Guide to Jazz, was one of the giants of American music. Monk had a unique improvisational style and made numerous contributions to the standard jazz repertoire, including Epistrophy, 'Round Midnight, Blue Monk, Straight, No Chaser and Well, You Needn't.