Year after year, children and adults alike are baffled by the mystery of how Santa really knows who's been naughty or nice. After much urging by the elves and Mrs. Claus, Santa has allowed his biggest secret to be revealed in the Elf on the Shelf: A Christmas Tradition. Touted as "The best thing since the Night Before Christmas" this gift set includes a light skin, blue eyed North Pole pixie-elf, hardbound children's book and keepsake box. Children can register their elf online and receive a special response from Santa.