Bob Rock produced Metallica's Metallica, better known as The Black Album.
Rock was already known for producing successful hard-rock records before working with Metallica, including albums by Mötley Crüe, Bon Jovi, Aerosmith, and the Cult. His appointment represented a new direction for the band after Flemming Rasmussen had produced its preceding albums.
The recording process was demanding. Metallica had developed a reputation for tightly controlled studio work, while Rock pushed the musicians to perform parts together and refine arrangements. The sessions at One on One Recording Studios in Los Angeles lasted roughly eight months and often became tense.
The album credits also list James Hetfield and Lars Ulrich as co-producers. That detail sometimes causes confusion, but Bob Rock is the canonical answer when a question asks for the album's producer. Rock continued working with Metallica on later projects, including Load, Reload, Garage Inc., and St. Anger.