How does Santa really know who's been naughty or nice?
The elf answers the age old question in The Elf on the Shelf: A Christmas Tradition^TM.

The Elf on the Shelf: A Christmas Tradition^TM is an activity the entire family will enjoy. Based on the tradition Carol Aebersold began with her family in the 1970s, this cleverly rhymed children's book explains that Santa knows who is naughty and/or nice because he sends a scout elf to every home. During the holiday season, the elf watches children by day and reports to Santa each night. When children awake, the elf has returned from the North Pole and can be found hiding in a different location. This activity allows The Elf on the Shelf to become a delightful hide-and-seek game.

Each Tradition-in-a-Box^TM comes with its very own scout elf, a hardbound children's book and a keepsake box for easy storage.