They didn’t invent heavy metal, but Judas Priest have been its most zealous defenders. Expanding the 1993 set Metal Works from two discs to four (plus a live DVD from a prime-era ’82 gig), this chrome-studded, leather-bound keepsake holds everything but the codpiece and exhaust fumes: a 30-year span of monster-truck hits, live tracks and B-sides, plus covers of Fleetwood Mac and…Joan Baez? For longevity, they assimilated biker fuzz and boot-boy oi!, S&M skullduggery, thrash and disco (even their ’86 synth-metal atrocity Turbo rates four tracks), never abandoning the metal qua metal (“Metal Gods,” “Heavy Metal,” “Metal Meltdown”) that became their signature. Rob Halford’s operatic, hypersexualized squeals, which seeded metal’s tortured homoeroticism for a generation, are never a whit less than way too much, and when the monster hits dry up in the middle of disc three, guitarists Glen Tipton and K.K. Downing rewrite the shred-guitar playbook. Priest are nothing if not generous: While Metalogy is coming out in time for the re-Halford-ized band’s reemergence on Ozzfest, it nonetheless offers a four-song footnote to the group’s dalliance with cover-band replacement Ripper Owens.

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