Sleep evolved in the early 1990's from the band Asbestosdeath, which had been established by Al Cisneros, Chris Hakius and guitarist Tom Choi. Asbestosdeath expanded to a quartet with the introduction of Matt Pike on guitar, and recorded 2 singles - "Dejection" for Profane Existence and the self released "Unclean". Choi departed, and would later found Operator Generator, It Is I, Noothgrush, and Las Vegas' Black Jets. Asbestosdeath recruited Justin Marler as replacement and the band adopted the new name, Sleep.
Their debut album Volume One was released in 1991. Frequently compared to bands like Saint Vitus, Sleep soon gained a devoted fanbase within the developing doom metal scene. The record also showcased the band's penchant for lysergic dirges. Marler quit the band soon after to take up life as a monk, leaving the band as a power trio for the recording of their Volume Two EP, which was released unofficially by Off The Disc Records in 1991.
The band's next album was sent to the independent label, Earache, as a demo. Recorded at Razors Edge studios in San Francisco, with Billy Anderson handling production, the tape showcased Sleep's love of all things retro, from the blatant Black Sabbath/Blue Cheer influences, to their fixation with 1970's-style Orange and Green Matamp amplification. The label immediately signed the band and released the tape exactly as it was received.
Sleep's Holy Mountain (1992) is widely considered a seminal album in the evolution of stoner metal. The album's release was followed by a potentially lucrative offer from London Records, and Sleep signed with them. Around this time, Earache released its first Black Sabbath Tribute album, and Sleep contributed a cover of "Snowblind".
Under their new contract, they began work on their third album, Dopesmoker, in 1995. Much to the dismay of executives at London records, Dopesmoker was comprised of a single song more than one hour long. London Records declared the album unmarketable and refused to release it. Sleep returned to the studio and then submitted their second attempt at the new album. They had retitled it Jerusalem, re-written some of the lyrics and trimmed it down to a "lean" 52 minutes, but it was essentially the same as Dopesmoker. London Records again refused to release it. Frustrated and generally unhappy with the situation, the members of Sleep decided to disband.
In 1998, Jerusalem was released posthumously as an "official bootleg" by a friend of the band. Sleep and their former manager had full knowledge of this and granted it their approval. In 1999, Jerusalem was given an official legitimate release by The Music Cartel in the US and Rise Above Records in Europe.
Finally, in 2003 the original version of Dopesmoker was officially released by Tee Pee Records. It is generally considered the definitive version of the album. An excerpted version can be heard on Jim Jarmusch's Broken Flowers original soundtrack.
Cisneros and Hakius later formed the band Om while Pike formed High on Fire.
In 2007 a CD compilation of both 7" releases of the pre-Sleep band, Asbestosdeath, was released on Southern Lord Records.