Arguably the best rock album of the decade, Aenima is a dark, disturbing journey through the ugly underbelly of the human mind. In short, "Aenima" is Tool's masterpiece. Tool explores the brooding, seething, anguished human psyche better than any band on the planet, and delivers its message of existential dread with utter conviction. The songs on "Aenima" constantly shift, morph and transform themselves, sometimes raging with fury, sometimes settling into relaxed interludes that still boil with a dark menace underneath their calm surface. Maynard James Keenan's vocal work is the key to Tool's power, heard to maximum effect in such songs as "Eulogy," "Stinkfist" and the title track. No singer in rock captures the ambivalence and terror of the human experience as well as Keenan. When he and his outstanding bandmates are at full speed, they're untouchable. "Aenima" will bore into your brain with all the subtlety of a jackhammer. Without this record, your collection can't be considered complete.