Four in One is the debut album by the group Sphere featuring pianist Kenny Barron, bassist Buster Williams, and Monk's former drummer Ben Riley, and his former saxophonist Charlie Rouse. The album was released by the Elektra/Musician label. Four in One was coincidentally recorded on the day of Monk's death in 1982, though the musicians were unaware of Monk's death during the recording session and had not planned the album as a memorial tribute.