Recorded in 1991, Volume One is the only Sleep album featuring original guitarist Justin Marler, who later left to become a monk in an Eastern Orthodox monastery. The parallel isn't coincidental; there's undoubtedly a transcendental purpose buried within the marijuana-infused riffs of Volume One. That’s not to say Sleep’s early work is as blissful or as trance-inducing as that of Om, the band that frontman Al Cisneros would form in 2005. One of the great things about early Sleep songs like “The Suffering” and “Anguish” is that within the numbing (and at times calming) riffs, there's still a lot of mud and grit. Though Sleep would tune into Black Sabbath's more swinging aspects on 1993's epochal Holy Mountain, these early songs are all about the doom and gloom. If “Catatonic” and “Numb” are emblems for the effect Sleep was aiming for, then “Nebuchadnezzar’s Dream”—with its ominous incantation “Majestic tree of life decays/Sun is set from sky to sea/Mankind meets its destiny”—shows the inspiration Sleep found in primordial imagery.