Bob Rock's 1989 album Dr. Feelgood helped Metallica choose him to produce The Black Album.
Rock produced Dr. Feelgood for Mötley Crüe, and Metallica admired the record's powerful, polished sound. That experience persuaded the band that Rock could help translate its own songs into a more focused and commercially potent production without removing their heaviness.
Metallica had previously worked with producer Flemming Rasmussen on several important albums, including Ride the Lightning, Master of Puppets, and ...And Justice for All. Choosing Rock therefore represented a significant change in the group's production team as well as in its musical direction.
The collaboration was not effortless. Rock challenged the band over performance methods, vocal delivery, lyrics, and the amount of work needed to complete each track. Despite the tension, the resulting album became Metallica's best-selling record and a major landmark in heavy-metal production.