Millions of unwary souls from every quadrant of Earth are swallowing a daily diet of quackery, conspiracy theory, bogus history and faux science. We haven't just turned off our bullshit detectors, we've permanently disabled them. And in so doing, Thompson argues, we've made for ourselves "a thrilling universe in which Atlantis is buried underneath the Antarctic, the Ark of the Covenant is hidden in Ethiopia, aliens have manipulated our DNA, and there was once a civilization on Mars."

What ties together all these ancient and not-so-ancient belief systems is, by Thompson's reckoning, simply this: They all purport to be knowledge without actually being knowledge. They are "misinformation packaged as fact."

As the Internet tears down traditional news portals, untested propositions go hurtling through cyberspace, vastly increasing the ability of bad information to take root -- that is, to look simply like new information. "A rumor about the Antichrist can leap from Goths in Sweden to an extreme traditionalist Catholic sect in Australia in a matter of seconds," writes Thompson. As for creationism, it is now less a religious phenomenon than a technological one. Sites like CreationWiki and Conservapedia and Kids 4 Truth (a primer in intelligent design) dress up their unsecular ideas in secular clothing -- and obliterate the difference between fact and faith more effectively than Sarah Palin ever could.

"If you believe one wrong or strange thing," writes Thompson, "you are more likely to believe another." Especially if you're seething with hostility toward political, intellectual and scientific elites. Counterknowledge, for all its transience, gives its owners an enduring feeling: They have been entrusted with the very secret they weren't supposed to know.