Programming ASP.NET AJAX offers you:
A high-level overview of the ASP.NET AJAX framework
Functional code that you can cut and paste for use in your own applications
The essentials of JavaScript and Ajax to help you understand individual technologies used by the framework
An organization that reflects the framework's packages, including Extensions, Control Toolkit, the Futures CTP, and the AJAX Library
Sidebars throughout the book that identify and propose solutions to potential security breaches
Ways to use the standards-based AJAX Library with other platforms, such as PHP
A complete chapter on the UpdatePanel control for making individual parts of a web page independently updateable -- one of the framework's most important elements

Released previously as Programming Atlas to cover the beta version of the Microsoft framework, this edition is fully up-to-date and expanded for the official 1.0 release of ASP.NET AJAX. Written by Christian Wenz -- Microsoft MVP for ASP/ASP.NET and AJAX Control Toolkit Contributor -- Programming ASP.NET AJAX contains many hard-to-find details, along with a few unofficial ways to accomplish things.