The Pleasure Principle is the third studio album, and debut album under his own name, by electronic music pioneer Gary Numan, released in 1979. Released the same year as Replicas (under the name Tubeway Army), The Pleasure Principle also went to number 1 in the United Kingdom and paved the way to chart success for a string of synthpop acts such as Ultravox, The Human League, Depeche Mode and Orchestral Manoeuvres in the Dark.
Numan completely abandoned guitars on the album. This change, coupled with frequent use of synthetic percussion, produced the most purely electronic and robotic sound of his career. In addition to the Minimoog synthesizer employed on his previous album, Numan made liberal use of the Polymoog keyboard, particularly its distinctive "Vox Humana" preset. Other production tricks included copious amounts of flanging, phasing and reverb, plus the unusual move of including solo viola and violin parts in the arrangements. Gary Numan was also influenced by Kraftwerk; the track "Cars" has the same musical "glides" as "Autobahn" and both used the same synthesizers.
Notable tracks included "Airlane", the lead-off instrumental; "Metal", sung from the perspective of an android longing to be human (covered by Nine Inch Nails on Things Falling Apart, Afrika Bambaataa on Dark Matter Moving at the Speed of Light and used as backing for Planet Funk's "Who Said"); "Films", acknowledged by Bambaataa as an important influence on the U.S. hip hop scene; "M.E.", told by the last machine on Earth (later used as backing for Basement Jaxx’s "Where’s Your Head At?"); the electronic ballad "Complex", a UK number 6 single; and "Cars", a worldwide synthpop hit recently covered by Fear Factory and sampled for Armand Van Helden’s "Koochy". "Cars" reached number 9 in the U.S. and even climbed to number 1 in Canada, helping make The Pleasure Principle Numan's strongest stateside showing, but lack of a strong commercial follow up meant he was tagged a one-hit wonder there.
Numan toured throughout the world in support of the album with a huge stage set including banks of neon lights and twin pyramids which moved across the stage via radio control. The live show was captured on record as Living Ornaments ’79 and on video as The Touring Principle. The support act on the UK leg of the tour was Orchestral Manoeuvres in the Dark. An expanded version of Living Ornaments '79 was issued on CD in 2005, and the final show of The Touring Principle was captured on the CD Engineers (released exclusively through Numan's official website) in 2008.
Of the bonus tracks currently available on CD, "Random" and "Oceans" were instrumental outtakes from The Pleasure Principle sessions, originally issued on vinyl with other previously unreleased tracks in 1985; "Asylum" was the instrumental flip of the "Cars" vinyl single; the live versions of "Me! I Disconnect From You" and "Bombers" made up the B-side of "Complex", having been recorded on tour and lately made available in their original context on the expanded Living Ornaments '79 CD, along with "Remember I Was Vapour" and "On Broadway". The latter two tracks first saw the light of day as a promotional single shipped with early pressings of the album Telekon in 1980; Numan's unlikely version of the classic "On Broadway" was dominated by a characteristic synthesizer solo by then-former (and soon-to-be-again) Ultravox band member Billy Currie.
There was a special gig dedicated to the album scheduled at Manchester Academy in November 2009, similar to Numan's previous tours for Replicas and Telekon.
Allmusic's Greg Prato rated The Pleasure Principle four-and-a-half out of five stars. He explained that "there is not a single weak moment on the disc" and that "the quality of the songs gets stronger and stronger as the album progresses". He concluded: "If you had to own just one Gary Numan album, The Pleasure Principle would be it." Robert Christgau rated the album a B. He stated that it was where "metal machine music goes easy-listening." He also stated: "[...] this time he's singing about robots, engineers, and isolation. In such a slight artist, these things make all the difference."