Thing is, the first examples are good (not great, good), and then it seems there are some components the author didn't really quite grasped -- like proxies -- and threw examples of things without them. In the case of proxies, the author created proxies that replicate the normal behaviour of objects and after reading it, you'll keep wondering why you should use them, as they do nothing different from the default.
Also, broken English. I'll be the first saying that I'm not the most impressive writer in the English language, but hell, some sentences really hurt. "we will be comparing" is one of those cases. And you'll find plenty of them. Plenty of "that is", plenty "therefore" and things like that just make the text tiring to read -- and it's not even a long read, just about 200 pages.