together with Davis' recordings from a February 18, 1969 "In A Silent Way" session The first track, "Right Off", was constructed from several takes and a solo Davis had recorded in November 1969. It also contains a riff based on Sly and the Family Stone's "Sing a Simple Song", most prominently at 18:44. Much of the track "Yesternow" is built around a slightly modified version of the bassline from the James Brown song "Say It Loud – I'm Black and I'm Proud". "Right Off" comprises a series of improvisations based on a B♭ chord, but changes after about 20 minutes to an E chord. "Yesternow" has a similar B♭ ostinato and shifts to C minor. It concludes with a voiceover by actor Brock Peters: "I'm Jack Johnson, heavyweight champion of the world. I'm black. They never let me forget it. I'm black all right. I'll never let them forget it." Liner notes accompanying a later release of the album provide a description of the music: According to The Guardians Tim Cumming, Jack Johnson abandoned jazz and the broad textures of Bitches Brew in favor of a concerted take on hard rock and funk, inspired as well by politics, the black power movement, and boxing. "[Davis] had a trainer who travelled with the band", Holland recalled. "He used to go to the gym every day. He was in his 40s, and that's prime time for musicians, when you're strong and all your faculties are there. He was playing incredibly." Ken McLeod, an associate professor of music history and culture at the University of Toronto, later said the bassline featured on "Yesternow" (and adapted from James Brown's “Say It Loud—I'm Black and I'm Proud”) is "potentially a deliberate allusion to the song's black power theme as it relates to the film's subject. That Davis was so influenced by boxing is also overtly manifest in the titles of pieces named after fighters that were recorded at several of the sessions, both before and after those that resulted in Jack Johnson. Such pieces include 'Johnny Bratton,' 'Archie Moore,' 'Duran,' 'Sugar Ray,' and 'Ali.'" Release and reception Jack Johnson was released on February 24, 1971, by Columbia Records to some commercial success—peaking at number four on Billboard magazine's jazz chart and at number 47 on the R&B chart—despite little marketing from the label. According to Davis, the record was originally released with the wrong cover: