Mötley Crüe's Dr. Feelgood persuaded Metallica to hire Bob Rock for The Black Album.
Released in 1989, Dr. Feelgood was produced by Rock and became one of Mötley Crüe's most successful albums. Metallica admired its powerful, clear production and believed Rock could help them improve the sound and presentation of their own material.
The choice represented a significant change from Metallica's previous studio process. The band had worked with producer Flemming Rasmussen on several earlier albums, including Ride the Lightning, Master of Puppets, and ...And Justice for All. Rock brought a different emphasis on performance, vocal delivery, bass presence, and cohesion.
Metallica's collaboration with Rock produced the self-titled 1991 album and continued through later projects. Although the band initially faced friction during the sessions, the result became its best-selling record and one of the most commercially successful heavy metal albums ever released.