THE ZWOLFTONSPIEL OF JOSEF MATTHIAS HAUER John R. Covach Introduction This study focuses on the music of the Austrian composer and the- orist Josef Matthias Hauer. It is probably safe to assume that Hauer is usually remembered, by English-speaking musicians at least, as the composer who developed a theory of tropes at about the same time as Schoenberg developed the twelve-tone system. One is generally aware that Hauer's thought may have influenced Schoenberg in the early twenties, even if it only prodded Schoenberg to publicize his discovery sooner than he planned. 1 Beyond this, however, Hauer usually re- cedes from musicological view, and less is generally known about his work from the thirties, forties and fifties. Perhaps it would surprise some to discover that Hauer, born in 1883-he was nine years younger than Schoenberg and two years older than Berg-composed music until his death in Vienna in 1959. Hauer certainly played a crucial role in the birth of the twelve-tone system in the Vienna of the early 1920's. It is well known that, at least for a time, Schoenberg took Hauer's ideas very seriously. Schoenberg even saw enough similarity between his work and Hauer's to fear the charge ofplagiarism. 2 Right from the start, however, Schoenberg also realized that he and Hauer held very different aesthetic stances. In an 149