Sleep is an American heavy metal band from San Jose, California. Guitarist Matt Pike and bassist and vocalist Al Cisneros have been the only constant members throughout its history, with several changes of drummers throughout their history. Critic Eduardo Rivadavia describes them as "perhaps the ultimate stoner rock band" and notes they exerted a strong influence on metal in the 1990s. The band first gained attention with their second album, Sleep's Holy Mountain (1992). However, conflict with the band's record company contributed to Sleep's breakup by the end of the decade. Sleep's third album, Dopesmoker, was released after the band's dissolution. The band reformed in 2009 and has played sporadic live dates internationally since. In 2018, Sleep surprise-released their comeback album, The Sciences, on Third Man Records, to critical acclaim.