Ms. McKeown has a post up that sheds more light on writing the book, on her own site. It sounds like all of the parts of the book will be available:
... The rest of the book will be published serially, so keep an eye out for the introduction and chapter 1 soon.
Ok ... will be making room in my schedule to read Chapter 3. The book really does sound like a big asset for WordPress, and those who use it!