I've been reading Tymoczko's 'Tonality: An Owners Manual'. It's very fascinating. It's full of diagrams (mostly spiral and circular) that illustrate voice leading geometry to explain not just classical functional harmony but also the many non-functional progressions heard in other genres like rock.
I wish though he explained how to follow certain complicated diagrams more fully. At about 150 pages in I got stumped for hours trying to make sense of one. 😵💫
