Formed in Birmingham, England in 1968, Black Sabbath was one of the most important influences on hard rock and grunge music. While the term "heavy metal" was taken from a Steppenwolf lyric and had already been applied to bands such as Cream and Led Zeppelin, in many ways Black Sabbath invented the genre. They were perhaps the first band to include occult references in their music, and they began to distance themselves from the blues-based music which was the norm, although they had started their career as a blues band.

Originally calling themselves Earth, they discovered another band with the same name. After renaming themselves Black Sabbath the group released their self-titled first album in 1970. Black Sabbath was recorded both quickly and inexpensively—it took only two days and cost six hundred pounds. In spite of that, the album reached number 23 on the American charts and would...