I keep forgetting how much I get a kick out of books that are nominally written for junior high students. I am primarily a mystery fan, but books aimed at junior high schoolers can offer thought-provoking puzzles, and they don't usually have as much violence and death as mysteries for adults! This book had plenty of thought-provoking mysteries and puzzles, and it wasn't obvious! It's science fiction/fantasy, but for the most part, it doesn't depend on some other world. And, it being for junior high, it did have a happy ending, as most books – even those not for junior high students – do. Highly enjoyable.