This CD should have strong appeal to listeners who like Ligeti's Lux aeterna, the work made famous by Stanley Kubrick's use of it in 2001: A Space Odyssey, and the centerpiece of this album. While the other pieces included, by Ligeti and Dutch composer Robert Heppener, don't sound just like the Lux aeterna, they inhabit similar soundworlds and reflect a similar aesthetic vision. Daniel Reuss leads the remarkably disciplined vocal ensemble Cappella Amsterdam through the woozy atmospherics of Lux aeterna with assurance and sensitivity to the work's subtly shifting textures and sonorities. The effect of the piece may be one of mystical improvisation -- a kind of slow-moving celestial glossolalia -- but it's notated with excruciating precision, and its vocal demands place it beyond the capacity of all but a handful of the world's most accomplished choirs. Cappella Amsterdam is a fairly small group, with 26 members, and its performance has a pristine clarity. There are listeners who may prefer a larger group singing the Lux aeterna, where the sheer numbers allow for a more opulent sound, but taken on its own terms it's hard to argue with this leaner approach. The ensemble brings the same precision to the less familiar but hugely appealing and equally demanding works, Ligeti's Drei Fantasien nach Friedrich Hölderlin and Heppener's Im Gestein, based on the poetry of Paul Celan. Both contain moments reminiscent of Lux aeterna's radiant haze, but also have sections where the text setting is clear and simple enough to make the words understood. The CD is especially attractive because of the addition of single movements from Ligeti's Sonata for solo viola, placed before and between the larger pieces. The music itself is gorgeously expressive (the program notes aptly describe it as "an imaginary folk music"), and the simplicity of the single melodic line serves as an aural palate cleanser, setting off the saturated richness of the choral works. Susanne van Els plays it with glowing eloquence. Harmonia Mundi's sound is atmospheric, but clean and clear. Highly recommended.