STEVEN D. LEVITT, a professor of economics at the University of Chicago, was awarded the John Bates Clark Medal, given to the most influential American economist under forty. He is also a founder of The Greatest Good, which applies Freakonomics-style thinking to business and philanthropy.

STEPHEN J. DUBNER is an award-winning author, journalist, and radio and TV personality. He quit his first career—as an almost rock star—to become a writer. He has since taught English at Columbia, worked for The New York Times, and published three non-Freakonomics books.