Pragmatic Ajax is in the Dave and Andy style, in which we delve into the world of building real Ajax applications using Ajaxian techniques.
The bulk of the book is server-side agnostic, but server-side technologies are obviously discussed in detail too (Java, .NET, Rails, etc). There is also plenty on surrounding topics such as UI design for ajaxian applications and the like.
One really fun chapter comes from Ben and I talking about “Building Google Maps in 2 hours”. This chapter will walk you through building a Google Maps-like Ajaxian user interface, and will dispel the myths that “you have to be a rocket scientist”.
Look for the Beta Book soon!