It consists of vocalist Maynard James Keenan, guitarist Adam Jones, drummer Danny Carey and bassist Justin Chancellor, who replaced founding member Paul D'Amour in 1995.

The group's efforts to combine musical experimentation, visual arts, and a message of personal evolution continued with Lateralus (2001) and 10,000 Days (2006), gaining critical acclaim and international commercial success.

Both Paul D'Amour and Adam Jones wanted to enter the film industry, while Maynard James Keenan, who had studied visual arts in Michigan, worked as a pet store remodeler.

Described by the band as "slam and bang" heavy music[11] and the "hardest sounding" six songs they had written to that point,[12] the EP included the singles "Hush" and "Opiate".

It expressed more diverse dynamics than Opiate and included songs the band had chosen not to publish on their previous release, when they had opted for a heavier sound.

Tool was scheduled to play at the Garden Pavilion in Hollywood but learned at the last minute that the venue belonged to the Church of Scientology, which was perceived as a clash with "the band's ethics about how a person should not follow a belief system that constricts their development as a human being.

[24] The boost in popularity gained from these concerts helped Undertow to be certified gold by the RIAA in September 1993 and to achieve platinum status in 1995,[25] despite being sold with censored album artwork by distributors such as Wal-Mart.

[29] Justin Chancellor, a member of former tourmate band Peach, eventually replaced D'Amour during the recording of the album, having been chosen over competitors such as Kyuss's Scott Reeder, Filter's Frank Cavanaugh, Pigmy Love Circus's E. Shepherd Stevenson, Jane's Addiction's Eric Avery, and ZAUM's Marco Fox.

[37] Responding to fan complaints about censorship, Matt Pinfield of MTV's 120 Minutes expressed regret on air by waving his fist in front of his face while introducing the video and explaining the name change.

[54] In January 2001, Tool announced a new album, Systema Encéphale, along with a 12-song track list containing titles such as "Riverchrist", "Numbereft", "Encephatalis", "Musick", and "Coeliacus".

Rolling Stone wrote in an attempt to summarize the album that "Drums, bass and guitars move in jarring cycles of hyperhowl and near-silent death march ...

Keenan stated of the minitour: "For me, being on stage with King Crimson is like Lenny Kravitz playing with Led Zeppelin, or Britney Spears onstage with Debbie Gibson.

On December 20 the two DVDs were released, one containing the single "Schism" and the other "Parabola", a remix by Lustmord, and a music video with commentary by David Yow and Jello Biafra.

Fifteen years into the band's career, Tool had acquired what Dan Epstein of Revolver described as a devoted "cult" following,[67] and as details about the band's next album emerged, such as the influence of Lateralus tourmates Fantômas and Meshuggah,[68] controversy surrounding the new Tool album surfaced with speculation over song titles and pre-release rumors of leaked songs.

10,000 Days sold 564,000 copies in its opening week in the U.S. and was number one on the Billboard 200 charts, doubling the sales of Pearl Jam's self-titled album, its closest competitor.

During a short break early the next year, after touring Australia and New Zealand, drummer Carey suffered a biceps tear during a skirmish with his girlfriend's dog, casting uncertainty on the band's upcoming concerts in North America.

[82] On July 15, 2014, Carey and Jones informed Rolling Stone that family commitments and an ongoing lawsuit are the key reasons for the delayed fifth album.

Cerebral and visceral, soft and heavy, melodic and abrasive, tender and brutal, familiar and strange, western and eastern, beautiful and ugly, taut yet sprawling and epic, they are a tangle of contradictions.

[125] Describing their general sound, AllMusic refers to them as "grinding, post-Jane's Addiction heavy metal",[53] and The New York Times sees similarities to "Led Zeppelin's heaving, battering guitar riffs and Middle Eastern modes".

[126] Their 2001 work Lateralus was compared by AllMusic to Pink Floyd's Meddle (1971), but thirty years later and altered by "Tool's impulse to cram every inch of infinity with hard guitar meat and absolute dread".

[127] Completing the band's rhythm section, drummer Carey uses polyrhythms, tabla-style techniques, and the incorporation of custom electronic drum pads to trigger samples, such as prerecorded tabla and octoban sounds.

[128] Keenan's ability as a vocalist has been characterized more subjectively by the Seattle Post-Intelligencer: After his performance during an Alice in Chains reunion concert in 2005, freelancer Travis Hay saw him as "a natural fit at replacing Layne Staley".

[129] Regarding his role in A Perfect Circle and Tool, The New York Times wrote that "both groups rely on Mr. Keenan's ability to dignify emotions like lust, anger and disgust, the honey in his voice adding a touch of profundity".

[131] For example, AllMusic wrote that he "alternately utiliz[es] power chords, scratchy noise, chiming arpeggios, and a quiet minimalism" in "Sober".

[136] On 10,000 Days, Keenan wanted to explore issues more personal to him:[136] the album name and title track refer to the twenty-seven years during which his mother suffered from complications of a stroke until her death in 2003.

[29] In 1997, Maynard James Keenan named Hejira by Joni Mitchell, Holy Money/Greed by Swans, Physical Graffiti by Led Zeppelin, Red by King Crimson, and Passion by Peter Gabriel as his five favorite records.

Tool have constantly expressed the massive impact that progressive rock pioneers King Crimson have had on their music; on a 2001 tour with them, Keenan joked: "Now you know who we ripped off.

[152] Other reported influences of Tool include Fantômas,[68] Devo,[153][154] Bill Hicks,[23] Rush,[155] Helmet,[156] Faith No More,[53] Bauhaus,[157] Meshuggah,[68] David Bowie,[140] Mike Patton,[68] Dave Lombardo,[68] and Jane's Addiction.

[12] Rolling Stone described this imagery as "evil little men dwell in a dark dungeon with meat coursing through pipes in the wall" and called it a "groundbreaking", "epic" clip.

[28] Later albums included artwork by collaborating artists: Ænima[170] and Salival featured works by Cam de Leon; Lateralus[171] and 10,000 Days[165] were created with the help of Alex Grey.