William John "Bill" Evans (August 16, 1929 – September 15, 1980) was an American jazz piano player. His career lasted 25 years. He was known for playing close groups of chords in his left hand, while playing melodies with his right hand. He was also known for playing in groups that featured him, a bass player, and a drummer. The groups dealt more with interaction and group-improvisation than jazz bands before them.