Even while becoming the most successful heavy metal band in history, Metallica has had to withstand the occasional personnel shift. So, join us as we dig into Metallica Lineup Changes: A Complete Guide.

Metallica’s origins can be traced to Los Angeles in 1981, when drummer Lars Ulrich placed a classified ad seeking like-minded musicians sharing his passion for New Wave of British Heavy Metal bands, and was answered by guitarist/singer James Hetfield. Over the next couple of years, they picked up lead guitarist Dave Mustaine and bassist Cliff Burton. But as they prepared to record their debut album, they fired Mustaine, replacing him with Kirk Hammett.

Mustaine's departure had a butterfly effect on the course of heavy metal, but it was, by no means, the last of Metallica's lineup changes. The core of Hetfield, Ulrich and Hammett has remained unchanged, but they've gone through several bassists. This included Burton's shocking death and, despite enormous commercial success, an uneasy 15 years with his replacement, Jason Newsted. Then, their producer Bob Rock served as a stopgap for an album, but the lineup has not changed since the arrival of Robert Trujillo in 2003.

Still, each new musician has brought something different to the band, and the stories of their departures run beyond the standard "creative differences" that we always hear about. You'll read about all of them below in our complete guide to Metallica's lineup changes.