Okay, so granted, it's not the first DHTML/Javascript book, but "Foundations of Ajax" is the first (that I can find, anyhow) book extolling the virtues and details of building Ajax web applications. It's still listed as pre-order on Amazon, but on Apress you can purchase and download the eBook right now for only $20 (regular book price is $40). the PDF version is about 38 megabytes in size and 260 pages in length. The whole Ajax thing is cool in my mind, and I have been doing a lot of reading about it lately. Ever since Outlook Web Access on Exchange 2003 and then Google Maps came out, I've been pretty amazed at what you can do with this technology. Now there's lots of interesting apps that run in a web browser, a little more than thin client, but not really a fat client either.

So, go get this book and start to put that XMLHttpRequest object to work for you. Go build something usable and cool. Probably the one big thing that impressed me about this book was the fact that it pushes a test-driven/test-first approach to development (using JSUnit) and the fact that it has so many detailed, in-depth code samples and discussions. It doesn't just present code samples though. It takes you through the how's and the why's, which is cool.

What's this Ajax stuff, anyhow, you ask? From the book description:

"Google Maps, Google Suggest, Gmail, Tada List—these are all examples of highly dynamic web applications. In the past, we had an awkward choice: a thick client or a thin client. With a thick client, we got rich user experiences but had to deal with an error-prone and time-consuming deployment process. With a thin client we got ease of deployment but had to sacrifice the user experience.

"Today we have a third choice: highly dynamic web applications that are nearly as feature-rich as their thick client brethren. Using Ajax techniques, we can provide our customers the rich user experience they have come to expect while still enjoying the ease of deployment that we’ve come to expect.

"An Ajax application is very similar to the web applications we’re already familiar with. The difference is that it incorporates an “Ajax engine” that negates the start-stop nature of traditional web interaction and drives the whole process along. A quick look at an Ajax application like Google Maps will demonstrate the improvement to user experience very clearly. Gone are the constant page-refreshes and instead, you’re presented with a smooth, responsive interface that seamlessly reacts to your requests.

"Leading technology companies are adopting these techniques, and pressure is increasing for other companies to do the same in order to compete. The bar has been raised in the web application world, and what was once considered impossible is now being realized. With the help of these revolutionary Ajax techniques and this groundbreaking book as your companion, you can lead the way and get ahead of the game."

The eBook version is available to buy online now for $20.00, right here (at least at the time of this post).