When Metallica began gathering together everything they had in their vaults to include in a super-deluxe, box-set reissue of their touchstone 1986 LP Master of Puppets, they realized they had a lot more material to work with than on the reissues of their first two albums. “The hardest part of it all was the ‘kitchen sink element,‘” Lars Ulrich tells Rolling Stone. “There’s a certain exaggerated, perverse beauty in just overwhelming people with as much stuff as possible, but there is also some line in the sand somewhere where it just gets to be too much. If we included everything from that time period, you would need a fucking forklift to get this thing into your house.”

Ulrich says he and the rest of the band were able to pare down the set’s contents by asking themselves, what would a fan want to hear? In addition to remastering the original album, they ultimately settled on a selection of riff tapes, demos, rough mixes, interviews and concert recordings that cover the making of the LP from the songwriting process to the last leg of the touring behind it. The concert recordings include gigs where they were opening for Ozzy Osbourne, a few headlining shows, their last concert with bassist Cliff Burton (who died in a bus accident while on tour) and, among others, their first with his replacement, Jason Newsted. The box set – out Friday – features vinyl, CDs, a cassette, DVDs, a hardcover book, reproductions of handwritten lyrics, buttons and a lithograph; the reissue will also be available in more affordable single-disc and three-CD versions.

In the 31 years since Master of Puppets came out, it has become one of the most influential albums in metal. The lightning-fast riffing of “Battery,” “Disposable Heroes” and “Damage Inc.” set the bar for thrash metal in the mid-Eighties, as it infiltrated the mainstream via Metallica’s opening slot for Osbourne’s tour, while tracks like the crushing “The Thing That Should Not Be,” moody “Welcome Home (Sanitarium)” and proggy “Orion” showed that the genre was capable of so much more than speed. Meanwhile, the intricate title track balanced furious and more introspective passages, and became the band’s anthem – the song they’ve played most at concerts and the most-requested song on their recent “Metallica by Request” tour. The record ranked Number Two (behind only Black Sabbath’s Paranoid) on Rolling Stone’s 100 Greatest Metal Albums list and has since been certified sextuple platinum.

In anticipation of the collection’s release, Ulrich and guitarist Kirk Hammett spoke with Rolling Stone about all the things they’ve documented with the reissue of Master of Puppets.