Ow, it seems heavy going! I mean, it's good stuff; detailed, well-organized, and accurate (as far as I can see). But in my mind, it just shouldn't be such hard

Ow, it seems heavy going! I mean, it's good stuff; detailed, well-organized, and accurate (as far as I can see). But in my mind, it just shouldn't be such hard work to understand. The title's clear: "from first principles". I can't complain! I'm only about a quarter of the way through; I need a rest now. I may edit later.