This was pretty good. It is an expansion of a story, Uncle Joshua & the Grooglemen, originally published in Bruce Coville's Book of Monsters. Both are good, but I feel like I sort of hamstrung my enjoyment of this novella by reading the short story. Putting that aside, this book succeeds in good world building. It doesn't hold your hand, it gives you just enough to keep on learning more, and the main character is easy to identify with. All in all, solid storytelling. If you read the short story it might hinder your enjoyment of this. I wish I had found this book as a kid. It would have immediately shot up to a favorite. So, since it IS a children's book (and deeper than most of its era), mission accomplished!