When the aliens conquered Earth, they chose one man to study. And, in exchange for ultimate power, this man sold out humanity lock, stock, and barrel, becoming the greatest traitor the world has ever known.But when the aliens leave -- and the traitor remains behind -- what is the rest of the planet to do? Especially since he can torture or kill with mere thought...Originally published in "Worlds of If" November 1961, here is a Silver Age science fiction story!