Many of us are being misled. Claiming to know the "pals" of presidential aspirants, dark secrets about public officials, and hidden causes of the current economic crisis, those who spread rumors know precisely what they are doing. They are sometimes able to derail political candidates, injure companies and reputations, even damage democratic governance. And in the era of the Internet, they know more about manipulating the mechanics of false rumors--social cascades, group polarization, and biased assimilation--than you do. They also know that the presumed correctives--publishing balanced information, issuing corrections, and trusting to the marketplace of ideas--do not always work. A pioneer in the effort "to design regulation around the ways people behave" ("The Wall Street Journal"), Cass R. Sunstein uses examples from the real world and from behavioral studies to explain why certain rumors spread like wildfire and what we can do to avoid being misled. Cass R. Sunstein is the Felix Frankfurter Professor of Law at Harvard Law School (on leave). His previous books include "Republic.com "and "Infotopia"; he coauthored "Nudge: Improving Decisions About Health, Wealth, and Happiness." People are being misled. Those who spread rumors know precisely what they are doing when they claim to know the "pals" of presidential aspirants, dark secrets about public officials, and hidden causes of the current economic crisis. They are sometimes able to derail political candidates, injure companies and reputations, even damage democratic governance. And in the era of the Internet, they know more about manipulating the mechanics of false rumors--social cascades, group polarization, and biased assimilation--than you do. They also know that the presumed correctives--publishing balanced information, issuing corrections, and trusting to the marketplace of ideas--do not always work. A pioneer in the effort "to design regulation around the ways people behave" ("The Wall Street Journal"), Cass R. Sunstein uses examples from the real world and from behavioral studies to explain why certain rumors spread like wildfire and what we can do to avoid being misled. "Cass Sunstein has written a crisp, provocative book on a worrying problem--the susceptibility of our electronified society to base rumors. He convincingly shows that the constitutional marketplace of ideas does not solve the problem."--Anthony Lewis "It often seems that rumors are the one element that can travel faster than the speed of light. In "On Rumors," Cass Sunstein helps us understand their incredible appeal, their power, and their dangers. A fun-tastic book."--Dan Ariely, James B. Duke Professor of Behavioral Economics, Duke University, and author of "Predictably Irrational ""What Sunstein says matters. Co-author of the bestseller Nudge, he's also Obama's nomination for U.S. regulation tsar. Going by this book, he'll make a fierce watchdog."--Aditya Chakrabortty, "The Guardian ""Truth doesn't always win in the marketplace of ideas. Lies spread too. Cass Sunstein explains why and he outlines what, in a world of Facebook, tabloids, and blogs, we ought to do about it."--Chip Heath, author of "Made to Stick: Why Some Ideas Survive and Others Die ""One of the main takeaways of Sunstein's book is that trying to correct misinformation-based rumors with the truth is often ineffectual, or worse, counterproductive. The act of repeating the lie reinforces it in the minds of the polarized."--Evan Lerner, "Seed"