Metallica is an American heavy metal/rock band whose early releases included fast tempos, instrumentals, and aggressive musicianship that placed them as one of the founders of thrash metal. As of 2003, the line-up features long-time lead guitarist Kirk Hammett who joined the band in 1983 and bassist Robert Trujillo a member since 2003 alongside James Hetfield and Lars Ulrich. Previous members of the band are lead guitarist Dave Mustaine who went on to found the band Megadeth, and bassists Ron McGovney, Cliff Burton and Jason Newsted. The band also had a long collaboration with producer Bob Rock, who produced all of its albums from 1990 to 2003 and served as a temporary bassist between the departure of Newsted and the hiring of Trujillo.
The band earned a growing fan-base in the underground music community and critical acclaim with its third album Master of Puppets, described as one of the most influential and "heavy" thrash metal albums. Metallica achieved substantial commercial success with their eponymous fifth album, The Black Album, which debuted at number one on the Billboard 200. With this release the band expanded its musical direction resulting in an album that appealed to a more mainstream audience.
In 2000, Metallica was among a number of artists who filed a lawsuit against Napster for sharing the band's copyright-protected material for free without any band member's consent.
Despite reaching number one on the Billboard 200, the release of St. Anger (2003) alienated many fans with the exclusion of guitar solos and the "steel-sounding" snare drum. A film titled Some Kind of Monster documented the recording process of St. Anger and the tensions within the band during that time.
Metallica has released nine studio albums, three live albums, five extended plays, 24 music videos, and 45 singles. The band has won nine Grammy Awards, and has had five consecutive albums debut at number one on the Billboard 200, making Metallica the first band to do so. The band's 1991 album, Metallica, has sold over 15 million copies in the United States, and 22 million copies worldwide, which makes it the 25th-best-selling album in the country. The band has sold more than 100 million records worldwide as of the release of their latest album, Death Magnetic (2008). As of December 2009, Metallica is the fourth best-selling music artist since the SoundScan era began tracking sales, selling over 52 million albums in the United States alone. On October 31, 2011, a collaborative album with Lou Reed, titled Lulu, was released.