Pro Web 2.0 Application Development by Jeff Dwyer is the first book on professional Web 2.0 principles that includes the Google Web Toolkit (GWT). GWT is one of the leading Java Ajax frameworks in market, and is very hot in terms of relative growth; it can be integrated with other broader Java frameworks like JBoss Seam and possibly Spring. The book's focus on a single, extremely rich, example "killer application" is what sets this apart from other GWT titles.