I am looking for a good book to learn about AJAX. Can anybody recommend good ones? I know I can go to www.asp.net site but nothing like reading a good book as compared to learning about it online.
If you're happy to learn the Microsoft AJAX way I recommend Professional ASP.NET 2.0 AJAX (http://www.amazon.com/Professional-ASP-NET-2-0-AJAX-Programmer/dp/0470109629).
I bought a copy as soon as it was out last year and I hardly put it down still.
Then if you want to get into really hard-core ASP.NET AJAX development get a copy of Advanced ASP.NET AJAX Server Controls (http://www.amazon.com/gp/product/0321514440?ie=UTF8&tag=encosia-20&linkCode=as2&camp=1789&creative=9325&creativeASIN=0321514440), that's my next purchase for sure.
As for bloggers I recommend the David Ward (http://encosia.com/), he looks at ASP.NET AJAX as well as a lot of jQuery. Jeol (http://seejoelprogram.wordpress.com/) who co-authored the AJAX server control book. Nikhil Kothari (http://www.nikhilk.net/Category.aspx?id=1), a developer on the ASP.NET AJAX team, also does a lot with Silverlight and wrote Script# (C# -> JavaScript compiler).
Good Luck!
I've learned Ajax several years ago by coding a little application from scratch (GContact). I made the choice to use no library, in order to learn JavaScript and Ajax.
I think it's always the best solution : to write a little useful application (so you'll use and maintain it).
To go then further, I've read Ajax Patterns and Best Practices and I think it's a great book about Ajax and how to use the best technique for a specified problem (a little bit like YUI Design Pattern library).
See the two books listed here: http://stackoverflow.com/questions/118565/how-do-i-call-a-web-service-from-javascript#118913
I have _**Ajax in Action**_ by David Crane, and _**Pragmatic Ajax**_ from the Pragmatic Programmers. Both of these are good. I lean slightly towards _**Pragmatic Ajax**_ because
(i) it's slightly shorter and
(ii) I personally like the way it attacks the problem, working through the construction of a single AJAX application.
Personally, I'm using ASP.NET AJAX in Action by Gallo... It covers all the expected bases and is easy enough to follow.