I was a bit disappointed in the textbook ("Twentieth-Century Music: A History of Musical Style in Modern Europe and America") for not spending more time on Gershwin, I have always regarded “Rhapsody” to be a masterpiece, however; if it is not, I would say that Porgy and Bess is. I feel that as far as tapping into a native American vernacular and making it into something artistic; Porgy is about as far as we have come (I know this is something of a sweeping statement and should you want to discuss this further, I can elaborate). But for that matter, I also feel that the musical “Show Boat” by Kern and Hammerstein is a work of considerable achievement that warrants some consideration. This led me naturally to Marc Blitzstein (another popular music and Broadway composer) as I am very familiar with his works from both a musical theatre background and from the 1990’s film by Tim Robins (although the film was very “Hollywood” in its approach to the way the story worked out).
Harry Partch was very interesting to me, I think something must have been in the air regarding the “old instruments” with the way both him and Varese fantasized about more and more exotic sounds. The main difference is that Partch sought to do something about it by actually creating new instruments to fulfill his needs for compositions. I viewed the documentary from the link you posted and enjoyed it very much (I wish the sound quality was better) in part 2 (also on YouTube) an ensemble plays the composition: Daphne of the Dunes, which I found to be a quite enticing and elegant piece of music. In some ways it had something in common with Gamelan music (probably the emphasis on pitched percussion and flocculating rhythms so common in that music). With regards to the Varese, his portion of the textbook left me somewhat depressed, thinking about an old man who was just borne a little too early to see the innovations in electronics that were just on the horizon. On another hand, I came to the conclusion that I would view Varese less as a composer and more as a musical philosopher (this is in fact how I view Jon Cage). I listened to Ionization but much prefer the piece Hyperism (which is available in score form in the accompanying anthology to the Morgan textbook) for it’s more pronounced use of pitched instruments and (to my ears) greater dynamic realization.
I would be fascinated to hear the piece for Koto and Orchestra by Cowell; I looked for a recording of the piece on Amazon.com but came up with nothing. I study the Guzheng (which is the parent instrument [sort of, really the Tse has a more legitimate claim as the parent] of the Koto). I also share very much Cowell’s affinity for eastern music, including that of Persia (I also study the Sitar and Dilruba, and while those instruments have become purely Hindustani over time they have some lineage from Persia – as does all Hindustani music). What I did listen to was, of course, The Banshee and the trio for harp, flute and violin. This music was actually my favorite because it resembles the kind of dreamy melodicism that appeals to my ears so much. The international aspect of his compositions is an absolute selling point for me; do you know if he included any Hindustani or Carnatic music theory in his pieces?