This encyclopaedic book proposes a sweeping reformulation of the basic concepts of Western music theory, revealing simple structures underlying a wide range of practices from the Renaissance to contemporary pop. Its core innovation is a collection of simple geometrical models describing the implicit knowledge governing a broad range of music-making, much as the theory of grammar describes principles that tacitly guide our speaking and writing. Each of its central chapters re-examines a basic music-theoretical concept such as voice leading, repetition, nonharmonic tones, the origins of tonal harmony, the grammar of tonal harmony, modulation, and melody. These are flanked by two largely analytical chapters on rock harmony and Beethoven. Wide-ranging in scope, and with almost 700 musical examples from the Middle Ages to the present day, _Tonality: An Owner's Manual _weaves philosophy, mathematics, statistics, and computational analysis into a new and truly twenty-first century theory of music.