Bob Rock was the principal producer of Metallica’s 1991 album, commonly called The Black Album.
Rock had already built a reputation producing major hard-rock records, including Mötley Crüe’s Dr. Feelgood. Metallica admired that album’s sound and hired him for their fifth studio record. His approach encouraged the band to record collaboratively, use more harmonic vocals, and focus on performances that sounded powerful and immediate.
The sessions were difficult. Rock pushed the musicians toward repeated takes and more polished arrangements, while the band was accustomed to a different recording process. The disagreements became part of the story documented in A Year and a Half in the Life of Metallica.
James Hetfield and Lars Ulrich also received assistant-production credits, but Bob Rock is the album’s principal producer. Flemming Rasmussen produced earlier Metallica albums, including Master of Puppets and ...And Justice for All.