THE 13TH CLUE

``What a terrible day,'' reads the diary, but ``at least they sang to me at school.'' What follows is a treasure-hunt ending, of course, in a birthday party; in this case, it's the clues along the way that intrigue: instructions spelled out in the grass, with clothes on a line, with a coiled jump rope or carefully laid sticks; to be read upside down or inside out, or by unscrambling an anagram or decoding a rebus—all imaginatively displayed in Jonas's clean, beautifully composed illustrations. In addition to the evidence of her diary, the birthday girl is seen only as a shadow—plus, once, as a reflection and (implicitly) as the recipient of a warm welcome at the end. Another handsome and appealing book from this unusually innovative artist. (Picture book. 4-8)