Written, performed and produced by Ulver, the album was released on 22 January 2016 via newly formed, London-based label House of Mythology.

[1] The music was culled from multitrack recordings made at twelve different improvisatory "free rock" live shows the band performed in February 2014, and later edited and enhanced in the studio by Daniel O'Sullivan.

[2][3] The album has been described as "Ultimately a piece of work that exists above and beyond any conventional live recording, rather a hallucinatory travelogue as potent an experience to bear witness to as it was to construct.

"[2] On 30 October 2015 the song "Cromagnosis" was broadcast on Baba Yaga's Hut via online radio station Resonance FM, and later uploaded to Mixcloud.

"Nowhere (Sweet Sixteen)" is a new arrangement of "Nowhere/Catastrophe", and "Ecclesiastes (A Vernal Catnap)" reinterprets the ending of "Tomorrow Never Knows"; both original songs are from Perdition City.

"[2] On 3 June 2015, on the band’s official website, in a statement titled "Only Theatre of Pain", Ulver announced Daniel O'Sullivan, working under the moniker "12", had taken the multitrack recordings and begun sculpting and editing hours of material in his North London home,[6] before Anders Møller, Kristoffer Rygg and Tore Ylwizaker got involved, completing the recordings at Subsonic Society and Oak Hill Studios, Oslo.

"[12] Benjamin Bland from Drowned in Sound said, "In a not dissimilar fashion to 2014's collaboration with Sunn O))), ATGCLVLSSCAP unhurriedly glides through its run time (a breezy seventy-nine minutes) without ever feeling ponderous.

Building up so many layers of gorgeous sound over its initial hour that its transformation into more traditional song craft near its conclusion feels more like the beginning than the end.

"[9] Jedd Beaudoin of PopMatters said, "Ulver creates its own world with this album, exists on its own terms and asks us to consider embracing something that is outside the norm but well within the human experience and worth the journey of transformation it takes us on.