Tarkus is the second studio album by English progressive rock band Emerson, Lake & Palmer, released on 4 June 1971 on Island Records.

It has been reissued and remastered several times, including a new stereo and 5.1 surround sound edition by Steven Wilson, with bonus and previously unreleased tracks from the original sessions, released in 2012.

He took patterns that Palmer was playing on his practise drum pads and found that they complemented runs that he had developed on the piano, and used this as a basis for material on Tarkus.

The group approached the album by having a centrepiece track in order to establish a concept, but a definite story or idea for it had not been discussed at this stage.

As with their debut, the band recorded at Advision Studios in London with Lake handling the production duties and Eddy Offord returning as engineer.

A subsequent meeting amongst the band and their management convinced Lake to stay, and he went on to contribute to the track and most of the other songs on the album[5] including the lyrics, for which he used the artwork as inspiration.

[7] Emerson wrote the first musical ideas for "Tarkus" from a 10/8 rhythm that Palmer had played on his practice drum pad backstage at a gig.

[7] Emerson wanted the "Aquatarkus" section to have a sound that resembled a snorkel tube as he was into scuba diving at the time, so he generated one from his Moog synthesizer and played it during the marching beat.

[6][9] Lake wrote the lyrics after the music was recorded; Emerson and Palmer considered the religious implication in the line: "Can you believe God makes you breathe, why did he lose six million Jews?"

[3][8] "Infinite Space (Conclusion)" features Emerson playing a 7-ft Bechstein grand piano, and came about from the band's decision to follow the profound lyrics on "The Only Way" with a laid-back piece.

Emerson said Palmer could mimic her mix of Greek and cockney accents "wonderfully", and recalled the confusion from some American fans who could not understand what it was about.

Another outtake unearthed for the reissue, "Unknown Ballad", was a song actually titled "Just A Dream" recorded during the sessions when Emerson and Palmer were out of the studio, featuring Lake on piano and his friend Gary Margetts (of the group Spontaneous Combustion) on lead vocal, with brother Tris Margetts on bass and Lake helping out on backing harmonies.

The album was packaged in a gatefold sleeve and features artwork by Scottish artist William Neal, whose armadillo has since become an iconic image in progressive rock.

[11] Neal was involved with the London-based CCS Associates which typically produced art for reggae albums but occasionally they were given other records to work on, which was the case with Tarkus.

"[12] It originated from one of Neal's initial designs of a machine gun with a belt of bullets replaced by a row of keyboard keys, which he inadvertently sketched on with a pencil during a phone conversation which produced the tank image.

[6] The gatefold presents eleven panels that illustrate the events of the title track, beginning with an erupting volcano, below which Tarkus emerges from an egg.

New Musical Express's Richard Green, who had given high praise to the band's debut, bemoaned that "there are some nice passages, but these are almost completely buried by the overall cacophonous ostentation.

"[24] On the other hand, Chris Welch at Melody Maker heaped praise, describing the title suite as "dramatic, probing, explosive, full of theatre and convincing grandeur.

"[25] François Couture, in a retrospective review for AllMusic, said that Tarkus is "a very solid album, especially to the ears of prog rock fans – no Greg Lake acoustic ballads, no lengthy jazz interludes".

"[17] Paul Stump's 1997 History of Progressive Rock praised the album's title track but criticized the "enervatingly portentous lyrics" and the traditional form of the solos (beginning and ending on downbeats, using blues voicings).

[27] In 1993, the album was digitally remastered by Joseph M. Palmaccio and released by Victory Music in Europe and Rhino Records in North America.