Tool is an American, three-time Grammy Award winning progressive metal band that was formed in 1990 in Los Angeles, California. The band has sold over 13 million records worldwide, and consists of drummer Danny Carey, bassist Justin Chancellor, guitarist Adam Jones, and vocalist Maynard James Keenan. Tool has hosted worldwide tours and produced albums which have performed well on international music charts due to their cult status in the world of music.

The band emerged with a heavy metal sound on their first LP at a time when the genre was dominated by thrash metal, and later reached the top of the alternative metal movement with the release of their second LP, Ænima, in 1996. Their efforts to unify musical experimentation, visual arts, and a message of personal evolution continued with Lateralus (2001) and their most recent album, 10,000 Days (2006), gaining the band critical acclaim and success around the world. Due to Tool's incorporation of visual arts and relatively long and complex releases, the band is generally described as a style-transcending act and part of progressive rock and art rock. The relationship between the band and today's music industry is ambivalent, at times marked by censorship and the band members' insistence on privacy.

During the 1980s, each of the future members of Tool moved to Los Angeles. Both Paul D'Amour and Adam Jones wanted to enter the film industry, while Maynard James Keenan found employment remodeling pet stores after having studied visual arts in Michigan. Danny Carey performed as a drummer for Green Jellÿ[3] and Carole King, and played in the Los Angeles area with Pigmy Love Circus.

Keenan and Jones met through a common friend in 1989. After Keenan played a tape recording for Jones of his previous band project, Jones was so impressed by his voice that he eventually talked his friend into forming their own band. They started jamming together and were on the lookout for a drummer and a bass player. Danny Carey happened to live above Keenan and was introduced to Jones by Tom Morello, an old high school friend of Jones and former bandmate of Electric Sheep. Carey began playing in their sessions because he "felt kinda sorry for them", as other invited musicians were not showing up. Tool's lineup was completed when a friend of Jones introduced them to bassist D'Amour. Early on, the band fabricated the story that they formed because of the pseudophilosophy "lachrymology". Although "lachrymology" was also explained to be an inspiration for the band's name, Keenan later explained their intentions differently: "Tool is exactly what it sounds like: It's a big dick. It's a wrench.... we are... your tool; use us as a catalyst in your process of finding out whatever it is you need to find out, or whatever it is you're trying to achieve."

Only Tool's first music video "Hush" (1992) features prominent appearances by the band members. Keenan, Carey, D'Amour and Jones (left to right) are pictured wearing parental advisory stickers covering their genitalia.

After only a few gigs, the band was approached by record companies,and only three months into their career they signed a record deal with Zoo Entertainment. In March 1992, Zoo published the band's first effort, Opiate. Described by the band as "slam and bang" heavy metaland the "hardest sounding" six songs they had written to that point, the EP included the singles "Hush" and "Opiate". The band's first music video, "Hush", promoted their dissenting views about the then-prominent Parents Music Resource Center and its advocacy of the censorship of music. The video featured the band members naked with their genitalia covered by parental advisory stickers and their mouths covered by duct tape. The band began touring with Rollins Band, Skitzo, Fishbone, and Rage Against the Machine to positive responses which Janiss Garza of RIP Magazine summarized in September 1992 as a "buzz" and "a strong start".