Hi all! To answer some comments I'm going to quote Capntastic, who tested the book for me and provided valuable comments and suggestions. Hope he doesn't mind! Capntastic explained why the book was a good alternative to the wiki, and I think his explanation is as good as any:
Trying to teach someone DF by pointing them to the wiki is like trying to teach someone math by sending them to the wikipedia article for "mathematics". All the information's there, but there's no way to tell what foundational knowledge you need.
Now, if you're already on this forum you are probably pretty well placed to just use the wiki at any time to learn precisely what you need. But for many people the wiki has proved a difficult starting point - and that's not a criticism of the wiki (it is superb), it is just not in the nature of wikis to provide easy-to-follow step-by-step explanations of what to do, when, and why.
One of the reasons I agreed to write the book is that I have met many people who have "bounced" off Dwarf Fortress despite the wiki and other learning resources. They've wanted to play, fired up the game, gone to the wiki, and then given up. As much as anything this book was written for these players - several of my testers went from knowing nothing about the game to getting a functional fortress up and running on their first go. Oh, of course, they often had a lot of !!FUN!! once fortress management got complex, but for most they were able to get far further into the game than they thought they would.
Anyway, if you're already playing, this book might not offer a lot to you, but it might explain a few things to friends who have tried, failed, and complain about Dwarf Fortress. They really have no excuse now!