Ed. note: This material was compiled and organized by David Papandrew, in the course of his preparation for qualifying exams in music history at Harvard (which he passed). It's been on GeoCities forever; GeoCities is going to be closing down (October 26, 2009), and I did not want this material to be lost. I have attempted to contact David, but have not heard back from him. See: Email from GeoCities, announcing closing.
Bartók, Bernstein, Cage, Babbit, Gershwin, Varese, Messiean, Stockhausen, Takemitsu.
See: Wikipedia List
** From A History of Western Music: "Through external circumstances and the force of his own genius he transformed this heritage and became the source of much that was characteristic of the Romantic period. But he himself is neither Classic nor Romantic; he is Beethoven, and his figure towers like a colossus astride the two centuries." [Donald Jay Grout. (3rd Edition with Claude V. Palisca.) W. W. Norton & Co., Inc. New York. 1973. p. 521.]