It's a really good book with lots of information. Granted, it's now outdated, but it lists and describes every ride, show, attraction, game, food establishment, and shop in all eight Six Flags parks (except for SFFT, which is a bit more brief because of the recent aquisition) and all the waterparks. There are also a lot of good pictures. The only thing missing is a map of each park, but the extensive information makes up for it.
-Nate