When Simeon Goldfarb announces that he will not sing Christmas carols with the rest of his class, Emily Berg decides to join his action. Though the teacher and principal make carefully correct responses to the children's stand for religious independence, they--and the rest of the school--are somewhat surprised and mystified by it, resenting the lack of Christmas spirit. Even Emily's twin, Sally, decides to go ahead and sing the solo in ""O Holy Night,"" since she has the best voice in the fourth-grade class. There is a small mystery when the school Christmas tree is knocked down and former best friend Petey accuses new boy Simeon; in solving the mystery (it was an accident), Emily and Simeon become friends, and Simeon agrees to join the extended Berg family Hanukkah celebration, taking part in the children's reenactment of the story of ""Judah and His Brothers."" A careful, balanced fictionalization of the pressures Jewish children feel from the unthinking preconceptions of their neighbors, presenting the range of Jewish observance (Simeon is Orthodox, the younger Bergs don't keep kosher although Grandma does) and of Christian attitudes (omitting the virulent) through likable, believable characters. A little long and didactic in comparison with Cohen's brief, beautifully poignant Thanksgiving story, Molly's Pilgrim, this should still catch readers with its (ironically) attractive red-and-green jacket and then entertain them while it heightens their sensitivities--or strengthens their resolve.