Between the two World Wars the pace of life quickened. Jazz became enormously popular in both Europe and America. In classical music, Aaron Copland and Arnold Schoenberg opened new horizons. Radio and sound movies popularized all forms of music, from Toscanini to Big Bands.

After World War I, Schoenburg introduced the 12-tone system, as revolutionary a step as Bach's tempering of the eight-tone scale had been. The dissonant new music that he made possible was not readily embraced by North American listeners, who were beginning to accept jazz-influenced swing music and the purer symphonic sounds of film scores and radio. Highlights include Schoenburg's Suite for Piano, Op. 25, footage of a 1934 Louis Armstrong performance of "Tiger Rag," George Gershwin's "I Got Rhythm," and Rossini's "William Tell Overture."