Ajax Design Patterns, a new O’Reilly book, based on Michael Mahemoff’s Ajax Patterns wiki is set to be released on June 1.

Book Description
Those of you familiar with Ajax (Asynchronous JavaScript and XML) know how useful the technology is for creating interactive web applications with XML-based web services and JavaScript in the browser to process the web server response. Responsive web applications with client-like functionality are the new wave of the Internet. Though Ajax is new, the enabling technologies that allow JavaScript and similar languages to transfer and manipulate XML data from server to web browser have been around for a while. Ajax Design Patterns provides best practices for web developers by investigating how others have successfully dealt with conflicting design principles. You will find sections on foundational technology patterns, programming patterns, functionality and usability patterns, and diagnosis/testing of Ajax applications. Ajax is all about usability, so the patterns in this book focus on delivering usability in the face of constraints, such as user capabilities and expectations, bandwidth limits, the stateless nature of HTTP, and the complexity of Javascript. These patterns also are a concise way to represent the Human-Computer Interaction knowledge embodied in the many Ajax applications on the market.

also see Professional AJAX on WROX