Tool have become one of the most popular metal bands in the world by developing a distinctive sound merging progressive rock and heavy metal. They are especially noted for their elaborate song structures and irregular time signatures, industrial rock and gothic leanings, and taboo-breaking stance.
Forming in LA in 1990, their first EP released two years later earned them support slots with the likes of Rage Against The Machine. Debut album Undertow (1993) sold platinum thanks to the single "Sober" and more successful touring. Ænima, dedicated to comic and friend of the band Bill Hicks, sold triple platinum and received widespread praise from reviewers. Legal problems with their label followed, leading singer Maynard James Keenan to form A Perfect Circle as a side-project. Tool weren't to release a new album until 2001, but despite the long break they had lost none of their creative touch. Lateralus was also released to acclaim and sold double platinum, although some commentators were unimpressed by the perceived self-indulgence of the 80-minute record. While Tool toured extensively, it took another five years for a follow-up: 2006's 10,000 Days sold over half-a-million copies in its first week, but was less well-received by reviewers than their previous albums.
