Engaging. Well done, which is hard for a book written in a child's voice. I really wanted to know what was going to happen, especially in the second half of the book, although I felt that the restraint that got the reader through the first part was a little stifling for the second half. I just wanted to know so much more than little Jack could tell me! But if he were old enough to tell me everything, I never would have made it through the first part, so.
I'm not sure I would recommend it, given the difficulty of the circumstances. I guess if you can stomach hard crime stories you'll have no problem with this novel, as the details are given with minimum gruesomeness. If you're just expecting for a novel about people's interior lives under unusual circumstances, you may emerge from this one feeling a little battered, as I did.