Chapter Two ofFreakonomics is titled “How Is the Ku Klux Klan Like a Group of Real-Estate Agents?” It deals with the power of information, and more particularly the abuse of information. The K.K.K. part of the story concerns a man named Stetson Kennedy who, in the 1940’s, went undercover and joined the K.K.K. in order to try to dismantle it. Kennedy is now in his late 80’s; we spent some time with him in Florida while researching our book, and thought he was amazing — a forgotten American hero. The wonderful radio show “This American Life” apparently agrees. (We would have said they were wonderful even if they hadn’t agreed; honest.) As of today, the upcoming edition of “This American Life” is scheduled to feature a segment on Stetson Kennedy’s undercover work, as related by Stephen J. Dubner. Find out where and when to listen here, by clicking the “Where to Listen” tab.