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...