Mob Rules

Mob Rules was the tenth studio album, released on 4 November 1981, the second with Ronnie James Dio and the first with Vinny Appice, who replaced Ward during the Heaven and Hell tour. Martin Birch produced and engineered. The first recording the band made after Heaven and Hell was the title track, for the film Heavy Metal, where E5150 is also heard. They wrote at a rented house in Toluca Lake in Los Angeles, bought a sound desk meaning to record in their own studio, and gave up when they could not get a guitar sound. The album was made at the Record Plant in Los Angeles.

Appice said the songs were put together by jamming. Dio said the writing was much louder than on Heaven and Hell, while Iommi remembered it as confusing, and thought drug problems, including the producer's, hurt the sound. Butler named The Sign of the Southern Cross as his favorite because it let him try bass effects. It was Birch's last album with the band, and he went on to work with Iron Maiden until he retired in 1992.

The sleeve is adapted from the 1974 Greg Hildebrandt painting Dream 1: Crucifiers. The album reached the Top 20 in Britain with two chart singles, The Mob Rules and Turn Up the Night, and went Gold in the United States. AllMusic's Greg Prato called it underrated. Neither Dio nor Appice made another Sabbath studio album until Dehumanizer in 1992.