Bob Rock was the producer who worked on Metallica’s The Black Album.
Rock was known to the band because of his production work on Mötley Crüe’s 1989 album Dr. Feelgood. Metallica admired that record’s powerful, clear sound and hired Rock for its next studio project.
The collaboration changed the band’s recording process. Rock encouraged James Hetfield, Lars Ulrich, Kirk Hammett, and Jason Newsted to record more collaboratively, rather than constructing many parts separately. He also pushed for stronger vocal harmonies and a more live-feeling performance.
The sessions were demanding. Rock and the band frequently argued about arrangements, performances, lyrics, and production choices. The finished album nevertheless became one of heavy metal’s defining commercial successes. Rock later produced several other Metallica projects, including Load, Reload, and St. Anger, although his relationship with the group remained closely associated with the landmark 1991 album.