Union is the thirteenth studio album by English progressive rock band Yes, released on 30 April 1991 by Arista Records. Production began following the amalgamation of two bands that featured previous and then-current members of Yes: Anderson Bruford Wakeman Howe (ABWH), consisting of vocalist Jon Anderson, drummer Bill Bruford, keyboardist Rick Wakeman and guitarist Steve Howe, and Yes, comprised at that time of bassist and vocalist Chris Squire, guitarist and vocalist Trevor Rabin, keyboardist Tony Kaye and drummer Alan White. The eight musicians signed with Arista and a combination of unfinished tracks by both groups were selected for Union. The album's sessions were problematic from the start, including disagreements between some of the musicians regarding the "merger" of the two bands, strained relations during the recording process, and decisions by the production team of Anderson and producer Jonathan Elias to bring in session musicians to re-record parts that Wakeman and Howe had originally completed.

Anthony John Selvidge, known professionally as Tony Kaye, is an English keyboardist, best known as a founding member of the progressive rock band Yes. Born into a musical family, Kaye was classically trained and intended to become a concert pianist before he developed an interest in jazz and contemporary rock and pop music. He joined several groups through the 1960s, including the Federals, Johnny Taylor's Star Combo, Jimmy Winston & His Reflections, and Bittersweet.