The first three chapters are all about theory, and they're really good.
"Hard" and "Soft" light are pretty easy to understand, and explaining how to manipulate the effective size of a light source to select for hard and soft light is really cool.
"Direct" and "Diffuse" reflection are pretty easy to understand.
The "family of angles" (as in the angles within which lighting may cause direct reflection) is very logical. It's also the difficult part to apply, because it varies with the distance between the photographer and the subject, the lens-length and what's currently in frame.
More later, time to go home.