Every hoax is a curtain, and behind it is a deceiver operating levers and smoke machines to make us see what is not there and miss what is. As P.T. Barnum knew, you can short-circuit critical thinking in any century by telling people what they want to hear. Most scams operate on a personal scale, but some have shaped the balance of world power, inspired explorers to sail uncharted seas, derailed scientific progress, or caused terrible massacres. A...