I studied the first 3 chapters of this wonderful book and learned a lot. I could not study it beyond that because my tryout kindle unlimited subscription expired today. :(
I had started reading chapter 4 but I have to be honest. I could not make sense out of the Circle of 4ths. But I'm sure if I had had more time to read further, the penny would eventually have dropped. It is generally very well written, but chapter 4 was difficult to follow.