Billy Strayhorn
Often overlooked because of his long and exclusive relationship with Duke Ellington and his Orchestra, Billy Strayhorn should be considered the 2nd greatest jazz composer and arranger of all time behind only Ellington himself. Although his job was to arrange for the Duke Ellington Orchestra, he found ways of putting his personal stamp on everything he wrote. He was Duke's right-hand man and was responsible for most of the vocal arrangements and arrangements of popular songs but when given the chance to compose his own pieces, he never disappointed. After the first rehearsal of a new arrangement of his, he would walk around the room and ask the players if they liked their parts. He would say "Do you like your part?"