Wavering Radiant is the fifth and final full-length album by American post-metal group Isis, released by Ipecac Recordings in 2009 and produced by Joe Barresi.

The album continues Isis' history of lengthy songwriting, yet presents a slight departure from the soft-loud dynamics and post-metal aesthetic which characterized previous releases.

[1] This, coupled with the lack of a deadline, meant that the process was more open-ended for the band, allowing more freedom to abandon failed avenues and giving ideas time to evolve.

"[2] Harris' drums and keyboardist Bryant Clifford Meyer's Hammond B3 lines were tracked over three and a half days at Sound City in Van Nuys.

This marked the first time a specialist drum tech was utilised by the band; Jerry Johnson, a veteran of projects with Def Leppard and Linkin Park, was recruited.

[13] Reviewers have discussed the presence of a theme, with Milton Savage deducing that "track titles would imply an underlying conceptual framework to Wavering Radiant, with 'Hall of the Dead' preceding 'Ghost Key', and 'Threshold of Transformation' closing the album in epic circumstances – Turner, it seems, has left our world behind for exploration of another beyond the lives led by mortal men.

Although reluctant to give any specifics, he has expressed snippets of conceptual background at times; this, however, doesn't extend to the reasoning behind the album's title, which he declined to elaborate upon.

[18] Jung's 1961 work, Memories, Dreams, Reflections, served as a specific source of inspiration for Turner, as he noted on his blog in a post preceding the album's release.

[21] Milton Savage tussled with the challenge of defining Isis' sound: "If it's not heavy – 'dense' is better description – and the band's purer metal roots have grown into a towering trunk from which sprout the most tangled of branches, both sturdy and incredibly delicate, then how does one take in the full picture and condense twelve years of unfaltering advancement to a single adjective?

"On past releases, Isis employed loud/soft dynamics to stunning effect, and while that element remains central to their sound, the best parts of Wavering Radiant suggest a more sophisticated integration.

"[25] Not all reviews held the album to be such a departure – for instance, Andrew Hartwig feels that "Wavering Radiant continues in the direction that Isis have been travelling since their inception, with an increasing prominence of melody and a greater focus on placid sections to balance out their signature crushing heaviness".

"[23] Nate Chinen, however, sees this variety as a vital component of the album's success, attesting that "Aaron Turner expertly alternates between a death-metal roar and a more human wail, using whichever better suits the needs of a song".

"[26][27] This view is shared by Roque Strew, who argues that "equally vital to the record's dense, hypnotic shape is Clifford Meyer's command of the keyboard [...] His blissful, knotty phrases, played on a dusty Hammond B3 or Rhodes, often recreate moments from the psychedelic and prog-rock past.

Robin Jahdi writes that "the Isis sound, debuted proper on the 2002 album, is still present and correct, but there's more subtle shifts in mood here, including when they take influence from outside (Tool's Adam Jones plays on two songs).

"[23] The rhythms of "20 Minutes / 40 Years" are described as "Pelican-like" by NME reviewer Ben Patashnik,[29] and No Ripcord's Sean Caldwell compares the album to Mastodon's Blood Mountain, citing its potential for "crossover" appeal.

[30] In late December 2008, Isis began to introduce a previously unheard track into their live setlists, prompting speculation from fans and critics as video versions circulated on the Internet.

[34] On March 24, Isis added the song "20 Minutes / 40 Years" to their MySpace page,[35] and a week before the album's release, made the entire record available for streaming.

Described as a "seven and a half minute epic",[52] the video, directed by Matthew Charles Santoro and released in November 2009,[52][53] opens with ferromagnetic fluid moving through an ambiguous, dark setting.

[22] AllMusic's William Ruhlmann felt that with regards to structure, "Wavering Radiant works as a single piece of music rather than a series of songs",[27] as Milton Savage of Drowned in Sound concurred that Isis have "construct[ed] their latest so that it's best experienced as a whole".

The Guardian's Jamie Thomson posits that "the Isis of old gave the impression they were enjoying their meandering jams just a little too much, leaving the listener a tad lost.

Here, they rein them in perfectly, and reward you with a colossal chorus for staying the distance",[57] while Nate Chinen, of The New York Times, feels that the release "upholds a deliberative truce between brute physicality and moody rumination".

[15] Other selections include "20 Minutes / 40 Years"[23] and "Hall of the Dead",[23][30][57] which Roque Strew argues "may be the lushest, most astutely crafted opener in the Isis discography".