This is an good book. It's slightly let down by source that comes with book and being able to reconcile that to book. I seemed to hit a roadblock at around page five, trying to get my head around the unusual way Wicket HTML pages get packaged. This was compounded by the fact there were so many versions of the pages with names like "Login.html".
If the author had spent a little bit of time talking about this and providing a readme roadmap, I'd have undoubtably have given this book 5 stars. Once you get past that initial hiccup, the book is pretty good reading.
Unfortunately things have moved on a bit with Wicket, since the book was written. I think the 'sands of change' were upon the author as he wrote the book. The last chapter takes a sneak peak at Wicket 2.0 So most of book is a bit behind the times. Also all package names of Wicket have changed too, since it's now an Apache project.
Wicket is a good component based web framwork technology that is easier to get your head around than JSF. I think it's better than Tapestry too.
One of the pluses for me was it gave an overview of how to integrate with Spring, so for me, a Spring addict that more than compensated for it being slightly out of date.
Also the author never responded to my emails from over a week ago which I think slightly shows a lack of courtesy. Although he could be on a vacation, in which case this could be forgiven. :)