Hysteria (Def Leppard album)

Hysteria is the fourth studio album by English rock band Def Leppard, released on 3 August 1987, by Mercury Records. The album is the follow-up to the band's 1983 breakthrough, Pyromania. Hysteria's creation took over three years and was plagued by delays, including the aftermath of drummer Rick Allen's accident that cost him his left arm on 31 December 1984. Subsequent to the album's release, Def Leppard published a book titled Animal Instinct: The Def Leppard Story, written by Rolling Stone magazine senior editor David Fricke, on the three-year recording process of Hysteria and the difficult times the band endured through the mid-1980s. Lasting 62 minutes and 32 seconds, it is the band's longest studio album to date.

Hysteria was the band's third and final album to be produced by Robert John "Mutt" Lange. The title of the album was conceived by Allen referring to his car accident, the amputation of his arm, and the ensuing worldwide media coverage surrounding it. It is the last album to feature guitarist Steve Clark before his death in 1991, although songs co-written by him would appear on the band's next album, Adrenalize (1992).

Although initial sales stalled outside the band's devoted fanbase, it soon became a worldwide commercial success, reaching number one on both the Billboard 200 and the UK Albums Chart. It is Def Leppard's best-selling album to date, selling over 20 million copies worldwide, including 12 million in the US alone, and spawned seven hit singles. It remains one of the best-selling albums of all time.