In her foreword to Penn's sugary tale about Chester, a young raccoon who would rather stay at home than go to school, Jean Kennedy Smith notes that the story is ``for any child who confronts a difficult situation, and for the child within each of us who sometimes needs reassurance.'' Its obvious message is delivered by Mrs. Raccoon, who tells her son that ``I know a wonderful secret that will make your nights at school seem as warm and cozy as your days at home.'' She then kisses his palm, and Chester feels the kiss ``rush from his hand, up his arm, and into his heart.'' Whenever he gets lonely, she advises, he is to press his hand to his cheek and ``that very kiss will jump to your face and fill you with toasty warm thoughts.'' As it may for youngsters in comparable situations, this ``secret'' works for Chester, who in turn kisses his mother's palm so that she, too, will be reassured. Sprinkled with hearts and flowers, Harper and Leak's paintings of the raccoons and their woodland habitat are pleasant if sentimental. Ages 3-8.-Publishers Weekly