If you fancy taking on one of the extraordinary imaginations of the 1920's and 1930's, then this is a very tempting pair of discs. Varese wrote extremely sparingly - like Webern, Barraque, Grisey and a few other important voices, his complete output fits onto just two or three CD's. The big works - Ameriques especially - are going to be perennial classics, for no one before or since has had that freshness of spirit combined with a masterly sense of symphonic drama.
This set carries with it a further special feature which some will regard as a plus and others a minor drawback. In producing it, Decca went back to the raw compositional materials, and the actual scores performed here are some distance from the more familiar versions that have become established in the repertory. On the one hand this is arguably more authentic; on the other, some of the earlier instrumental lines sound materially harder to play, and with this (and perhaps with the unfamiliarity of the players to the slightly more skeletal feel of the revised textures) comes an outcome that doesn't always pack the punch of some of the performances I have heard. Boulez for example recorded a mind-blowing disc of Ameriques, Arcana and Ionisation with the NYPO about 20 years ago, which still amazes me - if you can find that you should be sorely tempted, because some of the other works here, interesting though they are, are certainly less important.
Chailly clearly adores this music and he extracts wonderful precision from both the Concertgebouw (disc 1) and the very talented Asko ensemble (disc 2). This is vibrant music, complete with its Neanderthalic grunts, its wailing sirens and its exuberant percussion lines. I was converted long ago - if you don't know what to expect, just take one piece at a time; if you do, I doubt you'll be disappointed.