Have been listeing to a lot of Ives recently, and through this my attention has been turned to Ruggles too. For those who do not know he completed a tiny but perfectly formed oevre of nine completed and surviving works. His works are searingly intense, atonal, dramatic, very personal, moving. He worked painfully slowly, not having had any formal musical training, and worked at the piano, essentially by trial and error - playing a chord, listening, then correcting and trying again. He used to sit at the piano with Ives, play one of his soaring atonal melodies and shout "doesn't that twist yer guts!!"
Sun Treader (1926-31) is a truly astonishing work - at sixteen minutes long it is easily Ruggles' longest work, and it contains an intensity of expression and emotion that is of quite a rare order. Its not easy on the ear (deliberately so!), but it is utterly involving, and has a powerful beauty that is all its own. It's the apex of his achievement and for anyone even remotely interested in contemporary music it is surely a must.
Are there any good books on his life?
I've heard Evocations (4 chants for piano), Portals, Angels, Toys, some early songs, Sun-Treader and Organum on piano. I am yet to hear Men and Mountains, Vox clamans in deserto and Organum for orchestra and Exaltation... such a pity that Michael Tilson Thomas' complete works LPs have not been reissued.