A couple of weeks ago I got "Star Wars: The Visual Dictionary" and yesterday I received "Star Wars: Character Encyclopedia". Pretty cool, both of them .The best IMO is the "Character Encyclopedia", because it has more info and is more up-to-date. "The Visual Dictionary" is nice, but it only shows sets up to 2010 and the pics of the sets are a bit sparse for my tastes - I would rather have seen (WAY) more pics. Still, it brings a wealth of info on SW sets in general, and I hope a more updated edition comes out soon, though I doubt it will be out before the end of 2012, if ever. On the other hand, "Character Encyclopedia" covers up every minifig up to now, and it even shows at least some of the variants, so for a minifig collector I think it's an invaluable asset.
A cool thing about the books are the special minifigs that come as a bonus:
Both "Ceremonial Han Solo" and "Ceremonial Luke Skywalker" are only available through the books, and are a very nice addition to any SW fan who collects minifigs .