90 is in no way intended as the exhaustive retrospective of the oeuvre of an important artist (this can, and should, be done in the coming years by someone more qualified than me.) The actual chronology of these pieces, and in some cases who might have collaborated with Achim on them, remain a mystery. But the historical context of this music is undeniably compelling-it doesn't feel like hyperbole to suggest that these cascading, hypnotic cycles equal the best of contemporaries like Terry Riley, working half a world away on their own minimal masterpieces.For now, a celebration is sufficient-the portrait of an extraordinary life at 90, narrated in beautiful, intimate, innovative music.