Formed around 1990 in Los Angeles, California, United States, Tool is a band that is most noted for combining hard rock with a wide variety of progressive structures, irregular time signatures and lyrics that range from anger to philosophical and social matters. After performing a handful of shows in the Los Angeles area and up the West Coast, they toured in the United States with Rollins Band in the summer of 1992 in support of their EP Opiate. Their first full length recording, Undertow, was released in 1993.

Emerging with a groovy heavy metal sound on their first release, when the genre was dominated by thrash metal, they were later seen at the top of the alternative metal movement with the release of their second full-length studio album Ænima in 1996, the first recording the band made after original bassist Paul d'Amour left the band to form Lusk. After an ongoing evolution of their sound and continuous efforts to unify musical experimentation, visual arts, and a message of personal evolution on Lateralus (2001), their most recent album 10,000 Days (2006), as well as respective tours, they are generally described as a style-transgressing act and part of progressive and art rock.

Their aspirational work features exceptionally long or complex releases, controversial lyrics and cover art, and unorthodox music videos, which results in a rather ambivalent relationship between the band and today's music industry, at times marked by censorship, and the band's ongoing struggle for privacy.

Nevertheless, Tool receive critical acclaim, have won Grammy Awards, perform worldwide tours, and produce albums that top the charts in several countries. Between album releases, the band takes extended breaks that allow for collaboration with other artists to design award-winning album packaging, elaborate light shows and involvement in notable side-projects.

Currently the band consists of:

Danny Carey (Drums)
Justin Chancellor (Bass)
Adam Jones (Guitar)
Maynard James Keenan (Vocals)

They currently have 6 major releases:
Opiate (1992)
Undertow (1993)
Ænima (1996)
Salival (Live) (2000)
Lateralus (2001)
10,000 Days (2006)