Bob Rock helped shape Metallica's The Black Album after producing Mötley Crüe's Dr. Feelgood.
Metallica admired Rock's work on Dr. Feelgood, Mötley Crüe's 1989 studio album, and chose him to produce their next record. The decision was significant because Rock was new to the band's album-production team and brought a different emphasis to performance, arrangement, and vocal delivery.
Rock encouraged the musicians to record as a group and sought a more immediate live feel. He also challenged the band during repeated takes and discussions about lyrics. The sessions became famously intense, with disagreements between Rock and the members documented in the film A Year and a Half in the Life of Metallica.
Rock's role is sometimes mixed up with that of Randy Staub, who engineered the album, or George Marino, who mastered it. Michael Kamen arranged the orchestral parts for “Nothing Else Matters,” but he was not the album's producer.