Since its original publication in 1930, Henry Cowell's New Musical Resources has become recognized as one of the few seminal technical studies to be written by a twentieth-century composer. In 1971, Virgil Thomson hailed it as "a classic." For this new edition, David Nicholls has provided an explanatory essay and annotations to Cowell's text. The essay traces the sources for the book and attempts to place Cowell's theories in the broader context of musical modernism.