There is something about a shapeshifter--a person who can transform into an animal--that captures our imagination; that causes us to want to howl at the moon, or flit through the night like a bat. Werewolves, vampires, demons, and other weird creatures appeal to our animal nature, our "dark side," our desire to break free of the bonds of society and proper behavior. Real or imaginary, shapeshifters lurk deep in our psyches and remain formidable cultural...