Def Leppard's success through the '80s helped define not just the sound of the era's hard rock, but popular music in general. They'd already risen to multi-platinum success with their first three records, but 1987's blockbuster Hysteria broke through to unprecedented heights. The album's seemingly unending series of hit singles and the band's equally ongoing touring kept records selling, eventually making it one of the best-selling albums of the decade. Where The Collection: Volume One repackaged albums and rarities from the band's commercial peak throughout the '80s, Volume Two takes a look at their output through what would be a tumultuous and shifting '90s. This began with their fifth album, 1992's Adrenalize, which came not just as the tide of popular music was quickly shifting from metal excess to grunge angst, but also after the 1991 death of longtime guitarist Steve Clark. Rather than jumping ship to follow the trends, Adrenalize was a continuation of Def Lep's infectious hard rocking pop, and the record still topped the charts and sold respectable multi-million numbers. Though the group's next studio album, 1996's Slang, took steps away from their established formula, even its raw production and experimental dabbling couldn't disguise the blend of swagger and melody that made it a Def Leppard album. The Collection: Volume Two also includes 1993 B-sides comp Retro-Active, 1999's return-to-form Euphoria, and a small vault's worth of rarities from this phase. The rarities are made up largely of live recordings that only superfans and completists will absolutely need, but there's also a fair amount of alternate versions, outtakes, and songs from soundtracks the group was involved with throughout the '90s. Various demos, working tapes, and acoustic versions of songs like "When Love and Hate Collide" give insight to Def Leppard's creative process as they continued to evolve through a decade that was less than kind to many of the bigger names of '80s hair metal and arena rock.