I used this book to pass the exam, but its really a subpar book. And I'm quite surprised by that, given how Orin Thomas is one of the co-authors, and his first MS book (the 290 training kit), is among the very best I've ever read.
Before that I never really cared for who the authors were, but I knew about Orin Thomas from his pre certtutor.net (don't recall what the site was called before that) days, and he always was a thorough professional.
Perhaps MS press just rushed to get the book out as fast as possible?
Unfortunately, at the moment, you really don't have any other option than buying this book, as it is the only book available at the moment (mid March 2010) for this particular exam.
Keep in mind that there are quite a few errors in the book. There are two errata pages, but even then all the errors have not been adressed.
The syntax for unmounting images with dism on Page 119 is wrong, but has not been adressed. Not to forget the continuity error on the same page. It is damn annoying to get wrong syntaxes all the time.
Correct command; dism /Unmount-Wim /MountDir:c:\img (/commit or /discard).