On De-loused in the Comatorium, the Mars Volta approach rock & roll like it's an ascetic discipline, a calling that comes with lyric sheets as dense and impenetrable as the Kabbalah and a ritual of worship that's dervish-like in its intensity. Formed by vocalist Cedric Bixler and guitarist Omar Rodriguez after the split of their former band--Texan hardcore legends At the Drive-In, who splintered acrimoniously in 2001--the Volta are an unashamedly progressive outfit, dealing in grandiose arrangements that come on like Led Zeppelin fired through Saturn's rings.