Writing dynamic applications isn't that hard. Folks are awed by Google Maps, but it isn't rocket science (apart from the satellite pictures). As a special bonus, see how to implement your own Google Maps-like application using DHTML.
Very good book
Pragmatic Ajax: A Web 2.0 Primer (Pragmatic)
This is a very good book, if you want to jump into Web 2 development. Authors waste no time in getting you up and running with practical examples. Examples are chosen wisely, explanation is excellent. Just keep in mind that the book is what it says, it is a primer, besides Web 2 is a big topic, yet authors do a remarkable job.
A broad overview of AJAX
Personally, I don't really use this book too much. It is a very general primer to web 2.0 with AJAX. It covers the Dojo toolkit and Prototype / Scriptaculous JavaScript libraries, but doesn't show you the true power of JS and really leaves you wanting more.
However, if you are lost or new to the web development world, this book will give you a good foundation. I would recommend picking up the O'Reilly definitive Javascript book and Prototype / Scriptaculous "bungee" book by Pragrmatic Programmers immediately after.
Great and Comprehensive
I really liked this book as an introduction into Ajax and found it better than 4 other books I looked at. It has the basics as well as detailed examples using the top 4 frameworks. Usually a book chooses one and may contain a page or two about one or more other technologies. This is a great primer for anyone and it may even aid you in deciding which group of Ajax technologies to implement.
Mike
Excellent explanation with great examples
This book is everything one can want form such a book. Before I read this book, I knew nothing about AJAX, although I read few articles on the internet, I couldn't find such nice explanations and examples. Now I use AJAX wherever I can, and I can't immagine my life without it. Buy this book and you won't be sorry.
Excellent no bull
Well written and excellent, great info in the first 50 pages. Much better than the Ajax on Java for the nutshell which seems to worm around. This book tells it like it is. Just my opinion. I think anyone who is being inundated with Ajax boasting should read this and see what its all about.