Drat, you're on to me.
If you already know everything about Struts 2 and JavaScript, you're probably better off with tutorials ;) The book, however, does cover a fair number of edge-cases not often seen in tutorials, and romps across a number of topics not specific to Struts 2 itself: I really didn't want to re-hash the existing tutorials and S2 documentation, but rather try to create a "mentoring session" between myself and someone new to the framework and/or a number of best-practices in the S2,
testing, and web-app development areas.
(And it's never a crime to try to snag free schwag ;)
Dave