Well, this is not a java development book as much as it is a netbeans book. What I mean here is that this book is about using netbeans as an IDE and not how to be a java developer. Of course, since netbeans is a java IDE, this means that the book is full of java code, but it will not serve you to learn java as good as a book dedicated for that subject. To sum it up, this book is going to teach you how to make your java coding easier using netbeans.
Now, for your questions.
Is this book only for developing desktop applications? It covers no part of client-server architecture, or database connectivity?
Well, since it's on the IDE, it tackles both. Chapter 13 is on web applications, and chapter 15 is on GUI applications. As for DB connectivity & socket programming, I'm afraid that this is not a part of this book.
Can this book be used by a novice java user? Does this book assume knowledge of any third party libraries?
The editorial review on amazon says that this book is "Intended for Java developers of varying skill who may or may not be familiar with NetBeans IDE or Java IDEs in general".
NetBeans comes with pretty good documentation. How does your book complement the docs that come with the ide? Also, is the book written for the NB novice or is it also good for someone transitioning from earlier NB versions? I know there were big changes in both capabilities and look and feel from earlier releases.