Useful but becoming outdated
This book is great for experienced and curious users. It's quite technical for lay users and the way information is presented isn't terribly user-oriented.
But the biggest problem is that Six Apart has updated Movable Type in ways that make this book obsolete in some aspects and that make it necessary to translate concepts in others. At this point, it's probably not worth the trouble to buy the book, and also probably not worth the trouble to write this kind of book when updates are so extensive and frequent.
This book is difficult
Unless you already have solid experience writing software, you will find this book overwhelming. But it is better than the program documentation. There are few other choices. It looks like it was rushed to press and many of the examples don't quite work on my provider's server configuration, e.g., I don't have access to the unix command line so isn't always easy to envision the file structures. (If you didn't understand the last line, you might consider paying the folks at Movable Type to build your blog.)
But in all fairness, this is a difficult subject to explain. Since personal blogging is so new on the scene, it seems like the blog jargon is still a little fuzzy. Liberal use of Google helps. Since many of the concepts in blogging software are new to me, I would have appreciated a clearer explaination in the introduction, perhaps with some graphic illustrations. Some of the topics here, "Publishing with Movable Type" for example, are filled with examples and terminology that belong in a later section of the book. It would suffice to just give the reader a broader overview of how the software works.
In-depth and practical
Anyone who uses Movable Type on a regular basis needed the book. It covers all of the basics around installation, setting up blogs and writing entries. But then it goes into more advanced topics like alternating the template and adding plugins. And even more advanced topics like RSS, Atom, and writing your own plugins. This is thorough book that is well written and will cover everything you need to know to blog with Movable Type.