On Through the Night is the debut studio album by the English rock band Def Leppard, released on 14 March 1980. The album was produced by Tom Allom. It charted at No. 15 on the UK Albums Chart and No. 51 on the Billboard 200. The album features re-recorded versions of "Rocks Off" and "Overture", tracks from the band's original independently released EP, The Def Leppard E.P. Other tracks are re-recorded versions of early demos, some of which appeared on the First Strike and Warchild bootlegs. The album was certified gold by the RIAA on 18 November 1983 and platinum on 9 May 1989.
"Rocks Off", "Wasted", "Hello America" and "Rock Brigade" were released as singles. However, the versions of "Rocks Off" (titled "Getcha Rocks Off") and "Wasted" that appears on the singles is a different recording from that of the LP, as is its B-side, "Hello America". The single "Getcha Rocks Off" included the songs "Ride into the Sun" and "Overture".
The spoken word intro to "When the Walls Came Tumbling Down" was performed by Dave Cousins of Strawbs fame, although Joe Elliott had done the spoken portion in earlier live performances and demo recordings that showed up on some early bootlegs. In his biography, Cousins claims that he did his best Laurence Olivier impersonation for the song's intro.