Computer Science books usually fall into one of three categories:
1] The truly rare gems , books that you read from beginning to end, they don't feel like a chore to read. I've come across a few such books -"Head First: Design Patterns" is one of them.
2] The books that aren't quite perfect -maybe the content is too dry, or the technical details are a bit off, but all in all , your time is not wasted reading them (or even skimming). You get some use out of it, and you learn something new. Finally, there is the last category.
3] The absolute bottom of the pile, books so bad and in-cohesive, that they leave you furious after having read the garbage in the first place.
After having purchased this book, to study for the 70-503 exam, I can state without a doubt in my mind that this book clearly falls in the 3rd category of books and should be avoided at all costs. There are much better books out there for studying for the WCF exam (even if they aren't official training kits), and as a reference guide this book is useless. Heck, you'd be better off just studying from MSDN. You WILL fail the exam if this book is your only study material.
Large chunks of the book are just copied directly from MSDN, specifically the instrumentation and security chapters. Even the same code examples are copied, as well as the general formatting. You'll be trying to read areas of the book, not understand what the authors are trying to say, go to MSDN for clarification, only to realize that they are the same. Of course, just like a student attempts to avoid getting caught for plagiarism by changing the occasional words, the authors have made the same futile attempts. For example: compare the Performance Counter section on pg 312, with the corresponding article on MSDN. The authors have even decided to copy the full registry key entries, without thinking whether or not they are relevant for the exam -they are not. To make matters worse, when the authors weren't cutting and pasting from MSDN, they were reusing the same text from other areas in the book (for example, duplicate exam tips, pg 362, pg 345, and duplicate tables pg 361, pg 344).
The book is also missing important WCF information such as service contract operator overloading, streaming, serviceKnownTypes, onserializing, releaseContextMode, IErrorHandler, etc. These are good to know items for the exam, and any solid WCF reference book should include them. Even exam objectives that are stated to be in the book (in the tear-out section), are missing. For example "Manage consistency between life cycles, sessions, concurrency, and bindings" is missing from Chapter 2, Lesson 2. The authors also seem to have avoided important issues such as the default InstanceContextMode (it's PerSession), and mentioning that the Light Weight Transaction Protocol isn't supported by ANY binding.
Missing content would have been somewhat justifiable if there simply was no more room in the book to put it in, however instead the authors have filled the book with bloat, tons of it. Pointless exercises, overly verbose labs, condescending requirements, and useless practice questions. Does every chapter need to be prepended with the requirements, and that you require Visual Studio 2008 to read this chapter. Why do the authors insist on telling readers that they require 384megs of RAM and a 1024x768 screen? The WCF 70-503 is not a beginner exam, it's a given that users taking this exam will know how to use a computer and install/use Visual Studio. The sample exam questions were a poor emulation of the actual exam questions. The bundled CD offers no extra practice questions, instead it's just a repeat of the questions in the book. In fact, the bundled CD's (2 of them), offer nothing new to the book, and should not have been included -the Visual Studio trial can just be downloaded from Microsoft's website. Other bloat includes pointless tables that just fill space, i.e. Algorithm Suites and Distinguishing Values on pg 346, -don't worry you don't need to memorize it for the actual exam.
If you are serious about taking the exam, or you are looking for a good WCF reference book, I recommend reading "Programming WCF Services" by Juval Lowy instead. I fail to see how anyone could give this WCF training kit book a review of more than one star. Compare the two books and you will see that I mean, it's that clear cut. What a difference it makes, when the author actually knows what he's talking about.