Metallica hired Bob Rock to produce the album commonly called The Black Album.
Rock was known for his work with major rock acts, and Metallica had been impressed by his production on Mötley Crüe's 1989 album Dr. Feelgood. Although the band initially hesitated about bringing in an outside producer, it ultimately decided that Rock could help realize the record's potential.
The sessions were demanding. Rock encouraged the musicians to record more collaboratively and pushed for live-feeling performances, harmonic vocals, and a more prominent bass sound. The band was accustomed to a highly controlled process, so disagreements between the group and producer became a recurring part of the recording story.
Metallica's production credits also include James Hetfield, Lars Ulrich, and the band itself in various listings, but Bob Rock is the distinctive outside producer associated with the album. He continued working with Metallica on later releases, including Load, Reload, and St. Anger.