Paranoid was not only Black Sabbath's most popular record (it was a number one smash in the U.K., and "Paranoid" and "Iron Man" both scraped the U.S. charts despite virtually nonexistent radio play), it also stands as one of the greatest and most influential heavy metal albums of all time. Paranoid refined Black Sabbath's signature sound -- crushingly loud, minor-key dirges loosely based on heavy blues-rock -- and applied it to a newly consistent set of songs with utterly memorable riffs, most of which now rank as all-time metal classics. Where the extended, multi-sectioned songs on the debut sometimes felt like aimless jams, their counterparts on Paranoid have been given focus and direction, lending an epic drama to now-standards like "War Pigs" and "Iron Man" (which sports one of the most immediately identifiable riffs in metal history). The subject matter is unrelentingly, obsessively dark, covering both supernatural/sci-fi horrors and the real-life traumas of death, war, nuclear annihilation, mental illness, drug hallucinations, and narcotic abuse. Yet Sabbath makes it totally convincing, thanks to the crawling, muddled bleakness and bad-trip depression evoked so frighteningly well by their music. Even the qualities that made critics deplore the album (and the group) for years increase the overall effect -- the technical simplicity of Ozzy Osbourne's vocals and Tony Iommi's lead guitar vocabulary; the spots when the lyrics sink into melodrama or awkwardness; the lack of subtlety and the infrequent dynamic contrast. Everything adds up to more than the sum of its parts, as though the anxieties behind the music simply demanded that the band achieve catharsis by steamrolling everything in its path, including its own limitations. Monolithic and primally powerful, Paranoid defined the sound and style of heavy metal more than any other record in rock history. ~ Steve Huey

PARANOID proved to be Black Sabbath's most focused, consistent, and successful record. Leaving behind the amorphous, extended jams of their debut for focused songs and a more structured sound, Black Sabbath virtually wrote the book on heavy metal with the ominous, unforgettable riffs, thunderous rhythms, and dark themes on this release. There are some up-tempo rockers, the famous title track for one, but for the most part PARANOID oozes along like a bad dream, as on the slinky, creepy opener, "War Pigs," or the lumbering thud of "Iron Man" (which boasts one of the most indelible electric guitar riffs in rock history).

The album's title is apt: PARANOID is filled with an edgy aggression and lyrics about war, insanity, death, and destruction. Ozzy Osbourne's flat, affectless voice merges perfectly with Tony Iommi's fuzzed-out, sledgehammer power chords and the bruising bass and drum lines to create an intense, freaky, horror-show universe. There are elements of blues-rock and psychedelia (the floating "Planet Caravan," in particular), but Black Sabbath basically invents here what would become one of the most popular genres of music in the latter 20th century and beyond. Even after the millions of heavy metal albums that have followed in its wake, PARANOID stands as an all-time classic.