"Tarkus" is the title track of Emerson, Lake & Palmer's second album. The progressive rock epic lasts 20:35. It was the longest studio suite by the band until the three impressions of "Karn Evil 9". The name "Tarkus" refers to the armadillo-tank from the William Neal paintings on the album cover. The artist has explained that the name is an amalgamation between 'Tartarus' and 'carcass'. Consequently, the name refers to the "futility of war, a man made mess with symbols of mutated destruction." The song "Tarkus" supposedly follows the adventures of Tarkus from his birth, through a fight with a manticore, which he loses and concludes with an aquatic version of Tarkus named "Aquatarkus". Keith Emerson, when asked what work he is proudest of, named his "Piano Concerto" and "Tarkus".

Emerson, Lake & Palmer were an English progressive rock supergroup formed in London in 1970. The band consisted of Keith Emerson (keyboards) of the Nice, Greg Lake of King Crimson, and Carl Palmer of Atomic Rooster. With nine RIAA-certified gold record albums in the US, and an estimated 48 million records sold worldwide, they are one of the most popular and commercially successful progressive rock groups of the 1970s, with a musical sound including adaptations of classical music with jazz and symphonic rock elements, dominated by Emerson's flamboyant use of the Hammond organ, Moog synthesizer, and piano.