Though some purists claim to prefer the unbridled ferocity of 1986's Darkness Descends, most experts would agree that Dark Angel only reached their creative peak with 1991's Time Does Not Heal -- a veritable masterpiece of thinking-man's thrash metal.

An oxymoron, you say? Perhaps, but with this true colossus of a record, the thrash stalwarts provided what many consider to be the definitive statement in progressive thrash metal.

Just imagine what ...And Justice for All would have sounded like if Metallica had recorded it with the attitude of Kill 'Em All, and you'll get the picture.

Led by drummer, lyricist, sometime guitarist, and principal songwriter Gene Hoglan, the L.A.

quintet packed more riffs (246 total, according to enthusiastic press releases of the time) into this ambitious, long-running disc, than most of their Bay Area neighbors had managed in their entire careers.

Excellent tracks like "Act of Contrition" and "Psychosexuality" test the listener's endurance with their sheer length and complexity, but almost every piece is essential to the puzzle, and there is very little extra fat to speak of here.

Even more significant is the album's broad lyrical scope (on par with Anthrax's best efforts), exploring such sensitive, rarely visited issues as rape ("An Ancient, Inherited Shame") and child abuse ("Time Does Not Heal").

But Hoglan also delves in the more typical subjects of the genre, like religion ("The New Priesthood"), insanity ("Pain's Invention, Madness"), and social ostracism ("Trauma and Catharsis") with an eloquence and sobriety rarely seen.

And yet, despite all it's highbrow aspirations, Time Does Not Heal is first and foremost an amazingly brutal thrash metal album, its sound brought into crisp focus by Pantera and Soundgarden producer Terry Date in ways never achieved on the band's ill-recorded earlier efforts.

Sadly, Time Does Not Heal arrived in record stores toward the tail end of thrash metal's brief reign and never received its fair due, turning instead into a well-kept secret for knowledgeable fans of extreme music.