Where, Oh, Where's My Underwear?

Jaunty verse and amusing paper engineering mark this affable if undistinguished effort. (The book's subtitle proves misleading, however: only one of the six spreads contains pop-ups, and those of a rather ordinary variety.) Starting in his room, an appealing blue elephant conducts a search for the missing garment--despite his concern, he exhibits an almost constant grin. Pull-tabs and lifted flaps reveal sneakers under the rug, a long-lost sock poured from a cereal box, a gator peering from a dresser drawer--but no underwear. Until the final spread, that is, where a playground hosts an unusual cavorting crew. Saltzberg's illustrations exude a childlike insouciance, but his sing-song rhymes don't scan well (``I found a doll I thought / I'd never see again / I even found my skateboard / behind the sofa in the den''). Nevertheless, the notion of underwear--particularly in absentia --should draw chuckles from the lower end of the intended audience. Ages 4-8. (Apr.)