If Aaron Copland was the great mainstream arts politician of his time, distributing patronage to a wide variety of otherwise neglected composers who would remain personally indebted to him, Cowell was the great radical mover and shaker, helping establish the reputations of a large number of American composers, beginning with Charles Ives , in the course of a productive compositional career.
As a teenager, Cowell wrote and performed piano pieces that incorporated what he...