James Fletcher Hamilton Henderson, Jr. (December 18, 1897 – December 29, 1952) was an American pianist, bandleader, arranger and composer, important in the development of big band jazz and swing music. His was one of the most prolific black musical arrangers and his influence was vast. He was often known as Smack Henderson (apparently due to his college baseball hitting skills). Fletcher is ranked along with Duke Ellington as one of the most influential arrangers and band leaders in jazz history, and helped bridge the gap between the jazz and swing era.