Roger Keith "Syd" Barrett (6 January 1946 – 7 July 2006) was an English musician, composer, singer, songwriter and painter. He was a founder member of the band Pink Floyd, and was the lead vocalist, guitarist and principal songwriter during the band's early years, providing major musical and stylistic direction in their early compositions. He is credited with naming the band, but left the group in April 1968 and was briefly hospitalized amid speculation of mental illness exacerbated by drug use.

Barrett was musically active for fewer than ten years. He recorded four singles with Pink Floyd, the debut album (and contributed to the second one), plus several unreleased songs. In 1969, Barrett initiated his solo career when he released the single "Octopus", taken from his first solo album, The Madcap Laughs (1970). The album was recorded over the course of one year (1968–1969) with five different producers (Peter Jenner, Malcolm Jones, David Gilmour, Roger Waters and Barrett himself). Nearly two months after Madcap was released, Barrett began working on his second and final album, Barrett (produced by Gilmour and featuring contributions from Richard Wright), which was released in late 1970. He then went into self-imposed seclusion lasting until his death in 2006. In 1988, an album of unreleased tracks and outtakes, Opel, was released by EMI with Barrett's approval.