Artist extraordinaire, winner of the Caldecott Medal and three Caldecott Honors, Paul O. Zelinsky has created his first moving-parts book since the best-selling Wheels on the Bus -and it's a beauty. To the verses of "This Old Man," he has constructed an ingenious visual narrative. A young boy goes outside with his dog and skateboard. Along the way, children can push tabs, turn wheels, or lift flaps to see a different-but always engaging-old man appear out of hiding and play Knick-Knack, holding a numeral. By similarly clever mechanics, each old man's dog chases a bone, and the men roll home. A paper-engineering extravaganza at the end shows us where everyone has been heading and what playing Knick-Knack really means. With more moving parts than in his earlier book and fabulously appealing characters, this takes the interactive book to a new level.