1981's Mob Rules was the second Black Sabbath album to feature vertically challenged singer Ronnie James Dio, whose powerful pipes and Dungeons and Dragons lyrics initially seemed like the perfect replacement for the recently departed and wildly popular Ozzy Osbourne. In fact, all the ingredients which had made their first outing, Heaven and Hell, so successful are re-utilized on this album, including legendary metal producer Martin Birch (Deep Purple, Whitesnake, etc.) and supporting keyboard player Geoff Nichols. And while it lacks some of its predecessor's inspired songwriting, Mob Rules was given a much punchier, in-your-face mix by Birch, who seemed re-energized after his work on New Wave of British Heavy Metal upstarts Iron Maiden's Killers album. Essentially, The Mob Rules is a magnificent record, with the only serious problem being the sequencing of the material, which mirrors Heaven and Hell's almost to a tee. In that light, one can't help but compare otherwise compelling tracks like "Turn Up the Night" and "Voodoo" to their more impressive Heaven and Hell counterparts, "Neon Knights" and "Children of the Sea." This unhappy streak is finally snapped by the unconventional "E5150," a synthesizer-driven instrumental. Then, the unbelievably heavy, seven-minute epic "The Sign of the Southern Cross" delivers one of the album's best moments before unleashing the roaring title track. Side two is less consistent, hiding the awesome "Falling off the Edge of the World" (perhaps the most overlooked secret gem to come from the Dio lineup) amongst rather average tracks like "Slipping Away" and "Over and Over." Over the next year, the sh*t would hit the fan for Black Sabbath, and Dio's exit would mark The Mob Rules as the last widely respected studio release of the band's storied career

Black Sabbath, Vol. 4 is just a cut below its two indisputably classic predecessors, as it begins to run out of steam -- and memorable riffs -- toward the end. However, it finds Sabbath beginning to experiment successfully with their trademark sound on tracks like the ambitious, psychedelic-tinged, multi-part "Wheels of Confusion," the concise, textured "Tomorrow's Dream," and the orchestrated piano ballad "Changes" (even if the latter's lyrics cross the line into triteness). But the classic Sabbath sound is still very much in evidence; the crushing "Supernaut" is one of the heaviest tracks the band ever recorded

The original lineup of Black Sabbath possesses such a mythic quality that it's easy to overlook how far they slid by the time Ozzy Osbourne up and left the band...or how far they rebounded after they hired Rainbow singer Ronnie James Dio as his replacement. Countless compilations over the years have preserved the initial part of the story line -- celebrating the innovations of the first four albums with a near fetishistic quality -- but there has never been a good retrospective concerning the Dio years until Rhino released the aptly titled The Dio Years in early 2007. True, the Dio years didn't last all that long -- the singer joined in 1980 for Heaven & Hell, then lasted through one more studio album, the following year's Mob Rules, before departing under a shroud of controversy after 1982's botched live album Live Evil -- but Dio had a powerful impact upon the band and its legacy; these were the last years that Sabbath exerted pull as an active band, and after his departure they stumbled through various singers over the next decade before intermittently reuniting with Ozzy in the '90s. The Dio Years proves that during his brief time with the band, Dio did help Sabbath make music that could hold its own with some of the classic lineup's finest moments. With Dio as a frontman, the band was harder, nastier, and a little faster than the slow sludge of the early Sabbath records, but it fit in nicely with the New Wave of British Heavy Metal at the beginning of the '80s and it's aged very well. Some of it can sound silly -- Dio's lyrical obsessions always do -- but this is harder, heavier, better music than either Technical Ecstasy or Never Say Die! Anybody who's refused to give this latter-day incarnation of the band the time of day might find this compilation revelatory