Theory of Colours
Hauer was born in Wiener Neustadt and died in Vienna. He had an early musical training in cello, choral conducting, and organ, and claimed to have been self-taught in theory and composition. In 1918 he published his first work on music theory (a tone-color theory based on Goethe's "Theory of Colours"). In August 1919 he published his "law of the twelve tones", requiring that all twelve chromatic notes sound before any is repeated. This he developed and first articulated theoretically in "Vom Wesen des Musikalischen" (1920), before the Schoenberg circle’s earliest writings on twelve-tone technique.