Kids and grownups should be amply entertained digging up hidden treasure from a dozen different two-page tableaus, like "Baking Cookies": "I spy a boot, five arrows, blue hair,/A deer, four flames, a little green bear;/Five white beards, two three-string guitars,/Six raisin eyes, and three treetop stars." Wick's detail-rich photographs span from the realistic--like The Rainbow Express (an excitingly in-progress train diorama) and Arts & Crafts (a craft table crowded with thumbtacks, pipe cleaners, and the like)--to the more surreal, like Inventor's Workshop, a confabulation of live electrodes and steaming test tubes.

Ultimate Challenger makes a fine introduction to the 20-plus-volume I Spy series (Treasure Hunt, School Days, and Marzollo gladly adds value here with two pages of brand-new additional riddles. (Ages 9 to 12) --Paul Hughes