Today my guest is Professor Cass Sunstein, the Robert Walmsley University Professor at Harvard Law School. Prof. Sunstein graduated from Harvard College and Harvard Law School, after which he clerked for Justice Thurgood Marshall on the US Supreme Court.  From 2009 to 2012, he was Administrator of the White House Office of Information and Regulatory Affairs. He is also the founder and director of the Program on Behavioral Economics and Public Policy at Harvard Law School.  Professor Sunstein has written numerous New York Times best-selling books on behavioral psychology, including Nudge: Improving Decisions about Health, Wealth, and Happiness,  The World According to Star Wars and his most recent book, #Republic: Divided Democracy in the Age of Social Media.