Author: Gez Lemon
The section on Ajax explains the difference between asynchronous requests and traditional HTTP requests, techniques for parsing XML, and using JSON as a replacement for XHTML. Like all other sections of the book, the section is rich with examples, ending with two detailed examples for making connected select boxes and Ajax menus respectively.
You can get a feel for the quality of the book from its companion website, where you can download the code examples. The book is very well-written, and engages the reader. Whether you're a beginner or a seasoned scripter, if you care about standards and accessibility, then I can highly recommend this book.