Metallica was the band’s first album produced by Bob Rock.
Released in 1991 and commonly called The Black Album, it marked a major production change for the group. Flemming Rasmussen had produced Metallica’s first three studio albums, while ...And Justice for All was produced by Metallica and Rasmussen. Bob Rock took over for the self-titled record and helped the band create a fuller, clearer, and more commercially accessible sound.
Rock’s influence extended beyond engineering decisions. He encouraged the musicians to record more collaboratively, tightened arrangements, and demanded performances that captured the weight of the songs. The resulting album preserved Metallica’s heaviness while reducing some of the complexity and abrasive presentation associated with earlier records.
The answer is the official album title, Metallica, rather than the nickname The Black Album. Rock continued working with Metallica on later studio albums, including Load, Reload, and St. Anger, but Metallica was the first collaboration.