Over at Pixologic, they introduce two books that are edited by Sybex.
I tried to find out whether they are really about ZB 3.1 or 3.0.
I fear the latter...
I just received both books. They both look to be about 3.1. I havent had time to do more than scan them but from what I can tell they look very well done. Lots to learn from them both. They both came with a CD. Very nice.