Def Leppard, in many ways, was the definitive hard rock band of the '80s. There were many bands that rocked harder, and were more dangerous, than the Sheffield quintet, but few others captured the spirit of the times quite as well. Emerging in the late '70s as part of the New Wave of British Heavy Metal, the group actually owed more to the glam-rock and metal of the early '70s — their sound was equal parts T. Rex, Mott the Hoople, Queen and Led Zeppelin. By toning down their heavy riffs and emphasizing melody, Def Leppard were poised for crossover success by 1983's Pyromania, but skillfully used the fledgling MTV network to their advantage. The group was already blessed with photogenic good looks, but they also crafted a series of innovative, exciting videos, which made them into stars. They intended to follow Pyromania quickly, but were derailed when their drummer lost an arm in a car accident, the first of many problems that plagued the group's career. Def Leppard managed to pull through such tragedies and they even expanded their large audience with 1987's blockbuster Hysteria.

Def Leppard had its origins in a Sheffield-based group Rick Savage (bass) and Pete Willis (guitar) formed in their late teens in 1977. A few months later, vocalist Joe Elliott, a fanatic follower of Mott the Hoople and T. Rex, joined the band, bringing the name Deaf Leopard. After a spelling change, the trio, augmented by a now-forgotten drummer, began playing local Sheffield pubs, and within a year they had added guitarist Steve Clark, as well as a new drummer. Later in 1978, the recorded their debut EP Getcha Rocks Off and released it on their own label, Bludgeon Riffola. The EP became a word-of-mouth success, earning airplay on the BBC. The group members were still in their teens.

Following the release of Getcha Rocks Off, Rick Allen was added as the band's permanent drummer, and Def Leppard quickly became the subject of the British music weeklies. Soon, they signed with AC/DC's manager Petter Mensch, who helped them secure a contract with Mercury. On Through the Night, the band's full-length debut, was released in 1980 and instantly became a hit in the U.K., also earning significant airplay in the U.S., where it reached number 51 on the charts. Over the course of the year, Def Leppard relentlessly toured Britain and America, including opening slots for Ozzy Osbourne, Sammy Hagar and Judas Priest. High N' Dry followed in 1981, and it became the group's first platinum album in the U.S., thanks to MTV's strong rotation of "Bringin' on the Heartbreak." MTV would be vital to the band's success in the '80s.