Foundations of ASP .NET AJAX
OReilly.Programming.ASP.NET.AJAX.Sep.2007
Addison wesley advanced ASP NET AJAX server controls for NET framework 3 5 (2008)
ASP.NET AJAX Client Libraries
Building a Sample Application Using ASP.NET AJAX
Introducing Server Controls in ASP.NET AJAX
Using Server Controls in ASP.NET AJAX
Using the ASP.NET AJAX Control Toolkit (Part 1)