Their ubiquitous late-'80s singles filled arenas around the globe, but the power of Def Leppard's pop-metal mastery runs much deeper. The slash-and-burn “Rock Brigade”, party anthem “Wasted” and stomping “Hello America” reveal the band's early ambition and NWOBHM roots. The bass-driven “Billy's Got a Gun” imagines restless youth at a deadly nadir and the scorching instrumental “Switch 625” shows off fallen guitarist Steve Clark's dazzling chops. Relying less on bombast in the '90s, the Lepp's later ballads, like “Two Steps Behind” and “When Love & Hate Collide”, show an emotional maturity in sync with the band's toned-down progression into the new decade.