Can you believe we already have two books published on Atlas? Makes me think we have hit on something big here ;-)
Foundations of Atlas: Rapid Ajax Development with ASP.NET 2.0
Oh and I just noticed that Matt Gibbs and Bertrand Le Roy (both developers on the Microsoft Atlas team) recently published a nice short overview of Atlas server side support, mostly around using UpdatePanel correctly. I learned stuff when I read it so I am sure you will too!
Atlas UpdatePanel Control Add Ajax interactivity to your ASP.NET 2.0 web pages
How about you? Any favorite Ajax books? What book really needs to be written?