Where does a band go after stretching the boundaries of its genre as far as possible? Well, if you're Isis, you virtually abandon it. Since their inception as a sludge-metal act in 1997, each of the American quintet's expansive releases have experimented with, and further removed them from, their hardcore roots.
Although elements of their past remain, on this, their fourth full-length album, Isis delve deeper into prog- and post-rock, where songs build upon layers and morph into densely woven, repetitious cycles. Whereas the cuts on 2004's "Panopticon" erupted in a definitive climax, this time around they are left open, making the complex, constructed walls of sound even more mammoth despite being nowhere near as hard. And for the most part, vocalist Aaron Turner actually sings, only occasionally resorting to his usual hoarse growl. A slow burner, the captivating, restrained emotion of "In The Absence of Truth" reveals itself over repeated listens.