When I first discovered this book here on Amazon (it can be hard to find for some reason) I wasn't familiar with it, but I decided to take a chance on it and I'm glad I did.
Since one author's perspective about what's important, how much detail is required, and what usage examples best illustrate a topic can vary significantly from that of another author, I think it's helpful to have multiple reference sources available. I found the set (three volumes, of which I have two so far) to be fairly comprehensive with the right mix of clear, easy to follow, explanations and detailed examples. I'm happy to say that it also complements my other, sometimes drier, Java books quite well.
Writing styles vary, and the author is often too verbose, but finding the right voice for a broad audience where the knowledge level can vary considerably is a challenge. He errs on the side of using 15 words to describe what could easily be said in 10, and sometimes restates what he just said, making me want to strike sentences out with a red pen. That editorial criticism aside, I'm recommending it. The book is very readable and helpful, but if you have doubts, check out the "Look inside" option first.