One of the twentieth century's most important musical thinkers, the author did pioneering work in multiple fields, including computer music, tuning theory, and algorithmic and computer-assisted compositions. This book is a collection of the author's hard-to-find writings arranged, edited, and revised by the self-described “composer/theorist.” Tenney argued that “a new kind of music theory is needed which deals with the question of what we actually hear when we listen to a piece of music, as well as how or why we hear as we do.” His collection, which spans the years from 1955 to 2006, constitutes one of the most important bodies of music-theoretical thought of the twentieth century. Each article in this volume asks how new and radical musical ideas might emerge from how we hear. Selections focus on his fundamental concerns—“what the ear hears”—and include thoughts and ideas on perception and form, tuning systems and especially just intonation, information theory, theories of harmonic space, and stochastic (chance) procedures of composition.