When we're talking about influential metal bands, there is no more single influential band to heavy music than Black Sabbath ... by substance abuse, Vol. 4 found Sabbath at a creative peak ...

Black Sabbath is a pioneer of heavy metal — perhaps the genre's godfathers. Even so, the band was never one-dimensional in its sound. The same can be said about "Changes" from Vol. 4 (1972).It's ...

Metallica 's Kirk Hammett named one particular guitar riff that he believes "shifted heavy metal." ...