You can get a pretty good idea of the movement of his music over time in the newly released 2-CD anthology Patterns in a Chromatic Field, Music for Cello (Brilliant Classics 9401). The budget set features the cello of Marco Simonacci and the piano of Giancarlo Simonacci. Several sopranos and a French horn player augment the lineup for a couple of short pieces.
It's a sort of retrospective of Feldman's work from 1948 through 1981, with a disk and a quarter devoted to his later masterpiece that bears the title of the set, "Patterns in a Chromatic Field".
The way from beginning to end holds much fascination for anyone interested in Feldman's development from High Modernist to "Feldmanist". With the beginnings we have two very brief unpublished works from 1948 that show him firmly within the language of the moderns. From there we see a very gradual evolvement into the various facets of the quiet, inimitable Feldman way. "Projection 1" (1950), "Four Songs to Poems by e e cummings" (1951) "Intersection 4" (1953), "Two Instruments" (1958), "Durations 2" (1960), and "Voices and Cello" (1973) get worthy readings before we are launched into the lengthy and monumental "Patterns".
Of course concentrating on the repertoire for solo cello, and cello & piano--with the brief additions of vocals and horn--does mean that certain aspects of Feldman's middle and later music are not representable, such as the hauntingly quiet largess of "Rothko Chapel", but such things are inevitable. This is the small chamber ensemble side of his music, after all, and we cannot expect larger forced styles to be represented.
The long, later-period work "Patterns in a Chromatic Field " (1981) takes up the final 90 minutes of the set, but it is such a capstone work in Feldman's oeuvre that one does not feel its temporal weight as much as revel in the unravelling, so to say.
It is surely one his later masterpieces. Quiet, yes, uncanny like his earlier mature works, but structurally in a new Feldman zone, like his earlier works related to the high modern "mainstream" but at the same time apart from it, totally Feldmanesque. The liners to this disk mention Feldman's fascination with the oriental carpets of Anatolia. They are woven of patterns that do not follow the perfect symmetry of their more well-known Persian, etc., equivalents, but rather fill the space in a more randomly executed way. His later work has something of that. There is repetition, yes, but the cello and piano parts include variations, a-temporal and temporal correspondences and shifts in velocity that lay out in a way more intuitive than rigorously structured, at least to my ears.
It is highly distinctive, highly beautiful music. The Simonacci's do the music total justice. There have been other versions of this work available but of the ones I have heard none sound better.
And of course the mini-retrospective of works that span his career offers another reason why this one would be my choice--not to mention the budget price. To have these very engaging earlier works lead up to the "Patterns" opus gives you something, too, that the others do not, which is a temporal context for his final phase and a feeling for his development as one of America's most remarkable composers.
It's landmark music. It's a landmark release.