Black Sabbath are an English (England) rock (rock music) band, formed in Birmingham in 1968 by Ozzy Osbourne (lead vocals (Lead vocalist)), Tony Iommi (guitar), Geezer Butler (electric bass (bass guitar)), and Bill Ward (Bill Ward (musician)) (drums (drum kit)). The band has since experienced multiple lineup changes, with Tony Iommi the only constant presence in the band through the years. A total of twenty-two musicians have at one time been members of Black Sabbath. Originally formed as a heavy blues-rock band named Earth, the band began incorporating occult- and horror-inspired lyrics with tuned-down guitars, changing their name to Black Sabbath and achieving multiple platinum records in the 1970s. Despite an association with occult and horror themes, Black Sabbath also composed songs dealing with social and political issues such as drugs and war.

As one of the first and most influential heavy metal (Heavy metal music) bands of all time, Black Sabbath helped define the genre with releases such as quadruple-platinum Paranoid (Paranoid (album)), released in 1970. They were ranked by MTV as the "Greatest Metal Band" of all time, and placed second in VH1s "100 Greatest Artists of Hard Rock" list, behind Led Zeppelin. They have sold over 15 million records in the United States alone. Rolling Stone has posited the band as the heavy-metal kings of the 70s.

Vocalist Ozzy Osbournes drinking led to his firing from the band in 1979. He was replaced by former Rainbow (Rainbow (band)) vocalist Ronnie James Dio. After a few albums with Dios vocals and his songwriting collaborations, Black Sabbath endured a revolving lineup in the 1980s and 1990s that included vocalists Ian Gillan, Glenn Hughes, Ray Gillen and Tony Martin (Tony Martin (musician)). In 1992, Iommi and Butler rejoined Dio and drummer Vinny Appice to record Dehumanizer. The original lineup reunited with Osbourne in 1997 and released a live album, Reunion. The early/mid 1980s line-up featuring Iommi, Butler, Dio, and Appice reformed in 2006 under the title, Heaven & Hell (Heaven & Hell (band)), until Dios death on May 16, 2010.