Porcupine Tree were an English rock band formed by musician Steven Wilson in 1987. The band began essentially as a solo project for Wilson, who created all of the band's music. However, by late 1993, Wilson wanted to work in a band environment, so brought on frequent collaborators Richard Barbieri on keyboards, Colin Edwin on bass, and Chris Maitland on drums as permanent band members. With Wilson still in charge of guitar and lead vocals, this remained the lineup until February 2002, when Maitland left the band and Gavin Harrison was recruited as his replacement.
Porcupine Tree's early sound evoked a style of psychedelic rock comparable to that of progressive rock band Pink Floyd. Upon signing with Kscope record label in the late 1990s, the band approached a more mainstream alternative rock sound. By the early 2000s, the band signed to a major record label and shifted their sound again, this time in a more progressive metal direction.
After the release and tour in support of their tenth studio album, The Incident, their biggest commercial success to date, the band became inactive as Wilson committed himself to his solo work, and other members began working on their own separate projects. Wilson hasn't ruled out a reformation, but has no particular plans for it either.
During a career spanning more than 20 years, Porcupine Tree earned critical acclaim from critics and fellow musicians, developed a cult following, and became an influence for new artists. However, their work mostly stayed away from mainstream music, being described by publications such as Classic Rock and PopMatters as "the most important band you’d never heard of."