O’Reilly’s Definitive Guides are meant to be just that: definitive. By definition, one of these guides should be able to stand as the complete, exhaustive, authoritative text on a given subject. Say, for example, you’re stuck on a desert island and can only have one book on Tomcat for all time, of course you’re going to want Tomcat: The Definitive Guide. And if you only have room on your shelf for one book on Squid, there should be no question which book it will be.
That’s why I was excited to see the release of our latest, Ajax: The Definitive Guide. We have our fair share of good Ajax books, but if there was ever a subject calling for a definitive guide, it is Ajax.
Author Anthony T. Holdener, III became involved with Ajax when a manager pushed him to develop a Web GIS application that was unlike anything currently being developed in the industry. Once it was completed, he thought his experience would make a useful primer for others tasked with similar monumental undertakings. After looking at his proposal, his new editors had a different idea: they thought his writing would be perfect for a “Definitive Guide.” The next thing he knew, he was writing the 900+ page book we have today.
“I feel that Ajax is extremely important right now in terms of Web Development,” Anthony says. “On the horizon, I think we can expect issues with Ajax such as broken Back buttons and no Bookmarking capabilities to go away as browser makers modify their code to better accommodate for Ajax calls. I also think the resurgence of JavaScript will continue, and it will be hardened (as a language) so that application developers no longer shrug it off as a pseudo-language.”
As for Ajax best practices, Anthony has spread them throughout his book–you can see them best in his code examples–and the final two chapters of the book are all about best practices for developing and implementing web applications.
If you’d like to win a free copy of Anthony’s book, post a comment telling us what you’re doing with Ajax–or what you’d like do do–and we’ll arbitrarily pick a winner to receive the book. Please post by the end of the day on Thursday, Feb 28.
The winner of our last free book, Head First JavaScript, was Jim Jones, a Systems Analyst for a small public Midwestern University where he is part of a team that does a little bit of everything to keep the school’s systems running and productive. Thanks for sharing your comment with us, Jim. I hope you enjoy the book.

What I'd like to do with Ajax (which I must admit I'm only just starting with) is bring some life to life science applications. Specifically applications for protein structure prediction and protein interaction networks. A dynamic interface, that allows users to fetch protein sequences and related structures.
While the excitement of Ajax centers around large, complex web apps, what I do and what I think most developers do is use Ajax for progressive enhancement. Use it to make forms more interactive or to provide dynamically updated info on the page. While I would love to work on the former, I'm pretty happy with the latter.
I've been getting some good use out of Shelley Powers' "Adding Ajax" for progressive enhancement of a web application I'm working on (if you don't mind, I'll keep most of the details to myself, except to note that it involves both geodata and event data). making the application as user-friendly as possible has proven to be challenging, and I'm wondering whether I need to graduate to a more heavy-duty Ajax approach or whether that will actually *reduce* the appeal.
Another project I've been working on for a long time is a courseware solution that is rather different from existing solutions. One of the features is a custom XML vocubulary that gets transformed into HTML+Flash content. Right now, that XML is authored by hand and just checked for validity according to a schema, but I need to create an Ajax editor for it. Existing editors are mostly focussed on WYSIWYG HTML, which aren't really useful except as inspiration (TinyMCE, I'm looking at you!), and what I need is a validating structured XML editor.
BTW, I was wondering what the difference between 'Head First Ajax' and 'Head Rush Ajax' is. Their marketing and descriptions seem remarkably similar.
What's the difference between Head First Ajax and Head Rush Ajax? That's a good question. You can read what Brett McLaughlin, Sr. Editor of the Head First series, has to say about it here: http://www.oreillynet.com/headfirst/blog/2008/03/head_first_or_head_rush.html#more
Kathryn, thanks for the explanatory link!