Jack is a cut-paper frog, applied to the page, whom Walsh (Samantha, 1996, etc.) uses to explain the broadest elements of a fairy tale: the challenge, the mettle tested, the happily ever after. The story opens with a writer contemplating a fairy-tale project. There will be royalty involved, and trolls—and Jack. He balks: ``Leave me out. Fairy tales aren't safe—I saw those trolls.'' At the writer's coaxing, Jack reluctantly agrees to participate. Thus the tale unfolds. The princess is abducted by trolls, the king calls on Jack to save the fair maiden, the trolls fall to bickering and pose no problem, there's a rescue, and a return. Walsh cleverly unravels the mechanics of the tale as she merrily erects its structure, but that unraveling also defeats any possibility of tension or drama—the very stuff of fairy tales. The expressionless, unblinking, upright hero, his damsel, and their foes further drain the story of interest, past the intriguing opening. Pair this with real fairy tales at story hours, for children will love the idea of the protagonist being persuaded to take on his task, and will want to apply Jack's formula, not only to see when it ``works,'' but when it varies, as well. (Picture book. 4-8)