Harold, a bunny, has outgrown most baby things, but his thumb is hard to relinquish. Mother's teasing remark—''I might just hide it from you''—gives him an idea: he'll hide it from himself, in a book, or a mitten, or the clothes hamper—where he follows it. A party balloon gives him a better idea: he'll tie things to the thumb as fail-safe, nose-bumping reminders. The parents here are nicely nonjudgmental, while Harold provides a good model of solving one's own problem in one's own time. In the lively, amusing illustrations, he is clearly more boy than bunny, despite the ears. (Picture book. 3-7)