Category theory meets music meets cognitive theory. There's a huge conceit here, that the most powerful tools of mathematics can bring out further understanding of music. And I was unsure of it to start. But there's a payout here. The math illuminates musical structures in an elegant and deep manner. Along the way there's nearly as much to say about brain function and cognition as music. (Though they're clearly closely related.)
I'd say that the book's audience is necessarily limited, but that for those who can safely approach the book, it's nothing less than a remarkable achievement. I liken it to when, as a physics graduate student, I first encountered Arnold's Mathematical Methods of Classical Mechanics (Graduate Texts in Mathematics). Mathematical elegance applied to the world.
