Thelonious Sphere Monk (/θəˈloʊniəs/, October 10, 1917 – February 17, 1982) was an American jazz pianist and composer. He had a unique improvisational style and made numerous contributions to the standard jazz repertoire, including "'Round Midnight", "Blue Monk", "Straight, No Chaser", "Ruby, My Dear", "In Walked Bud", and "Well, You Needn't". Monk is the second-most-recorded jazz composer after Duke Ellington, which is particularly remarkable as Ellington composed more than a thousand pieces, whereas Monk wrote about 70.