My daughter's been studying manga for some time now. She's why I requested the book. So I'll let her tell you what she thought.
With a shrug of the shoulders, she said, "It was good. Nothing I didn't already know, though. That kinda sucked. I'd likely recommend it for newbies only."
So there you have it. Newbies only.
I will say, in a see of manga art books, nothing about this one stands out. Because she gave such a short review and I have no knowledge of the artform, I flipped through some of her other manga art books. They're mostly all the same, with slight variations here and there, but it seems they all hold roughly the same information. Then again, I'm no expert on the subject.