Tool is an American rock band from Los Angeles, California. Formed in 1990, the group's line-up includes drummer Danny Carey, guitarist Adam Jones, and vocalist Maynard James Keenan. Justin Chancellor has been the band's bassist since 1995, replacing their original bassist Paul D'Amour. Tool has won three Grammy Awards, performed worldwide tours, and produced albums topping the charts in several countries.

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 and Keenan performed for Green Jelly, and Carey played with Carole King and Pigmy Love Circus.  Keenan and Jones met through a mutual 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. Carey happened to live above Keenan and was introduced to Jones by Tom Morello, an old high school friend of Jones and former member 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 cited as 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."  After almost two years of practicing and performing locally in the Los Angeles area, the band was approached by record companies, and eventually 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 music and 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, Fishbone, Rage Against the Machine, White Zombie, and Corrosion of Conformity, to positive responses, which Janiss Garza of RIP Magazine summarized in September 1992 as a "buzz" and "a strong start".

Who were some band members?
Tool's lineup was completed when a friend of Jones introduced them to bassist D'Amour.