"Things Ain't What They Used to Be" is a jazz standard from 1942, with music by Mercer Ellington and lyrics by Ted Persons. It is a 12-bar blues in a major key. In 1941, a strike against ASCAP kept Duke Ellington's songs off the radio, so the band played pieces by his son Mercer and by Billy Strayhorn; Mercer wrote this song. Jazz historian Chris Tyle argues that Mercer most likely wrote the melody and that his father arranged it for the band. Johnny Hodges and His Orchestra recorded it in Hollywood on 3 July 1941, with Hodges playing it first. The single was issued on Bluebird on 20 March 1942, with "Squaty Roo" on the B-side. Charlie Barnet and His Orchestra recorded it in 1942, reaching number eight on the Harlem Hit Parade. Duke Ellington recorded it for Piano Reflections (1953) and played it in the film Cabin in the Sky (1943). Later versions were made by Dave Brubeck, Ella Fitzgerald (as "...And You Better Believe It"), Charles Mingus and Oscar Peterson. The song is most often played as an instrumental. It is the opening music of the film Soul (2020), and an instrumental version was the closing music of The Tonight Show Starring Johnny Carson.
