This is another one of those "Sniper Topics" that I like, again from PAKT Publishing.
Approximately 280 pages of drill down on Object Oriented Client Side development in JavaScript using the Microsoft AJAX Client Libraries.
Not only does this text enumerates the namespaces in the Microsoft AJAX Client Libraries, and provide good coverage of the Client Component Framework, but it teaches all the "whys" along with the "How Tos".
If your building AJAX applications and Microsoft's AJAX technology is at the center of your work then this book is a "must read".
Click on the book image above to check it out on Amazon.com