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. 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.