Dawn Cook follows up her strong "First Truth" with a solid sequel, which picks up most of the threads from the first but leaves plenty of space for further adventures. The sequel syndrome hasn't hit "Hidden Truth," and fans of Cook's first book won't be disappointed. The evil Keeper Bailic has the First Truth book, but he can't open it. Believing that the piper Strell is the person who can, he tries to teach Strell magic -- not knowing that Alissa is really the blossoming Keeper. While Bailic frustrates himself with Strell, Alissa is learning magic from the raku-Master Talo-Toecan (also known as "Useless"), except that she seems to be far ahead of where she should be -- with more powers than she should have. And there's a friend of Useless's named Lodesh, who is charming, weird, interested in Alissa, and totally mysterious.