Track listing : . 1.Hang Up Your Hang Ups (Herbie Hancock, Melvin ‘Wah-Wah Watson’ Ragin, Paul Jackson) – 07:29 . 2.Sun Touch (Herbie Hancock) – 05:11 . 3.The Traitor (Herbie Hancock, Melvin ‘Wah-Wah Watson’ Ragin, Johnson, Shorter) – 09:38 . 4.Bubbles (Herbie Hancock, Melvin ‘Wah-Wah Watson’ Ragin) – 09:02 . 5.Steppin’ in It (Herbie Hancock) – 08:41 . 6.Heartbeat (Herbie Hancock, Melvin ‘Wah-Wah Watson’ Ragin, Paul Jackson) – 05:16 .
Musicians : Herbie Hancock – synthesizer, piano, electric piano, ARP Odyssey, ARP Pro Soloist, Oberheim, Fender Rhodes, Clavinet . Wayne Shorter – alto and soprano saxophone . Jay DaVersa– trumpet . Bud Brisbois – trumpet . Bennie Maupin – bass clarinet, alto flute, saxello, bass flute, tenor saxophone, soprano saxophone, percussion . Dick Slide Hyde – tuba and bass trombone . Garnett Brown – trombone . Ernie Watts – flute and saxophone . Jim Horn – flute and saxophone . Dewayne McKnight – electric guitar . David T. Walker – electric guitar . Wah Wah Watson – synthesizer, voice bag, electric guitar . Henry E. Davis – electric bass . Paul Jackson – electric bass . Louis Johnson – electric bass . Harvey Mason – drums . James Gadson – drums . Mike Clark – drums . Stevie Wonder – harmonica on(5) . Bill Summers – percussion .
Production Produced by David Rubinson, Herbie Hancock . Jack Leahy – engineer . David Rubinson – engineer . Fred Catero – engineer . Phill Brown Mastering . George Horn – mastering .
Packaging : Ren Deaton Productions – art direction . Dario Campanile – art direction .
Recorded 1974-75 at Wally Heider Studios, San Francisco, Village Recorders, Los Angeles, Funky Features, San Francisco, Crystal Studios, Los Angeles .
Released on August 22, 1975 by Columbia.