Book 1 of the work deals with the theory of music under the traditional headings of harmonics, rhythm, and metre. It depends heavily on Aristoxenus (4th century BC), but with some "intriguing additions", apparently from a source from the classical period.Winnington-Ingram (1984), p. 377. Book 2 (said by Winnington-Ingram to be "extremely interesting") discusses the importance of music in the education of the young and in the moral life of individuals. Book 3 discusses the arithmetic of music and explores from the point of view of Platonic philosophy the analogies between numbers in music and numbers in the physical world.
