Volume Four is the fourth instalment in the series of box sets collecting Def Leppard's complete catalogue, covering the years 2015 to 2023. Alongside the albums Def Leppard, Diamond Star Halos and Drastic Symphonies it holds demos, live recordings, alternate mixes and collaborations selected by Joe Elliott himself, including a previously unreleased cover of The Beatles' Revolution. The book features photography by Ross Halfin, new band interviews and liner notes by Paul Elliott.

This edition is a 6-CD box set with a hardback book.