The Kronos Quartet turns in a spectacular performance of three unusually dissimilar Terry Riley compositions grouped under the title Requiem for Adam. Ostensibly the three parts of Requiem are based on the memory of Adam Harrington, the son of Kronos's David Harrington, but none of these works is particularly funereal. The perky, Bartók-influenced "Ascending the Heaven Ladder" gives way (unaccountably) to the harsh electronics of the composer-assisted second movement, "Cortejo Funebre en el Monte Diablo," which in turn leads to the energetic third movement, "Requiem for Adam." This music might have a hard time finding a new audience, but Riley fans--as well as Kronos enthusiasts--will revel in the music and the warm studio ambience. However, the final work here, a five-minute improvisational knockoff called "The Philosopher's Hand," finds Riley on the piano in a deeply meditative mood that could have gone for another hour. It promises much for the future of solo piano music from this gifted composer.