We've released a new version of the Maven Book - version 0.4. Highlights from this release include:
General improvements to Part I (courtesy of Brian Fox)
A new chapter covering M2Eclipse (courtesy of Bruce Snyder)
A new chapter on Maven Assemblies (courtesy of John Casey)
A Revised Version of John's Site Generation Chapter.
On Deck: A chapter on POM optimization by Brian Fox. Brian wrote some initial content for a chapter covering POM optimizations, I'm going to revise and extend that content to fit an entire chapter. Expect a Alpha 0.5 release some time this week.