Bob Rock produced Metallica's The Black Album during sessions centered at One on One Recording Studios in Los Angeles. The album's credits list Rock as producer, with James Hetfield and Lars Ulrich receiving assistant production credits.
Recording began in October 1990 and continued into 1991. The band also spent about a week at Little Mountain Sound in Vancouver, while final overdubs and mixing took place at A&M Studios in Hollywood. These multiple locations are why One on One is best understood as the principal recording studio rather than the only studio used.
Rock's production emphasized a tighter, heavier, more polished presentation than Metallica's earlier records. He encouraged the members to perform more as a unit and demanded numerous takes when necessary. The difficult sessions were later documented in A Year and a Half in the Life of Metallica, giving fans an unusually detailed view of the album's creation.