I do have a note of critique, I think there is actually little theory in the book. I really read it in one week-end, so i guess it will take you about 8 hours fulltime. On the other hand that can be an advantage to
The book triggers me to find nice extensions for my websites, I cannot wait to try out some stuff in the book. I see this as a compliment. Well in short, I like the book and if you are clean in the area of ajax and want to learn something about it in a week-end, this is your book.
Within the next few weeks i will try some of the existing frameworks, I did have a short look at the demo from Matt Raible: Matt Raible ~ Equinox and ajax