Metallica, released in 1991 and nicknamed The Black Album, was the band's fifth studio album. It followed Kill 'Em All, Ride the Lightning, Master of Puppets, and ...And Justice for All.
The record marked a significant change from the band's earlier albums. Metallica retained heavy and aggressive elements, but used simpler song structures, slower tempos, more prominent bass, and a more polished production style.
The shift helped the band reach listeners far beyond the thrash-metal audience. Songs such as “Enter Sandman,” “The Unforgiven,” and “Nothing Else Matters” became enduring radio and concert staples.
Although the group had already built a major following, the fifth album was its first to debut at number one on the Billboard 200. It remained at the top for four consecutive weeks and eventually became the band's best-selling album.