This book explores the means by which the operas of Debussy and Bartók transform the structures of the traditional harmonic system into a new musical language. Antokoletz formulates new theoretic-analytic principles and describes how these principles link various historical and cultural as well as philosophical and psychological issues of the early twentieth century within the operatic milieu. The new musical language described here is based almost exclusively on interactions between folk modalities and their more abstract symmetrical transformations.