CHRISTMASTIME is Sandra Boynton's humorous and compassionate carol to the season of warmth and giving, celebration and tradition. And tradition, to Boynton, is anything that happens every Christmas without fail: like trimming the tree, a fruitcake from the Rossiters, the crunch underfoot of your most precious ornament, and the customary search for scissors at four A.M. Christmas morning. With guest appearances by Santa and his reindeer, Boynton's familiar menagerie reveals the many joys and satisfactions that make Chrismastime such a universally special season: the thrill of finding the right gift for someone you love, and affording it; the personal gratification of wrapping all the gifts early; and the wonder of Christmas morning, when you realize you forgot to label them.