Master of Reality is the third studio album by Black Sabbath. Released in July 1971, it is widely regarded as the foundation of doom metal, stoner rock, and sludge metal. It was certified double platinum after having sold over 2 million copies. Master of Reality was Black Sabbath's first and only top 10 album in the US until 13 forty-two years later. Black Sabbath was formed in Birmingham in 1968 by guitarist and main songwriter Tony Iommi, bassist and main lyricist Geezer Butler, singer Ozzy Osbourne, and drummer Bill Ward. Black Sabbath is often cited as pioneers of heavy metal music. The band helped define the genre with a clutch of groundbreaking albums in the '70s.