Most survivors of Economics 101 leave the course feeling no great urgency to pick up a book on the subject as leisure reading. One very unconventional book changed that: Steven D. Levitt's 2005 Freakonomics became an international bestseller, racking up sales of more than four million copies. Fans have waited eagerly for this follow-up and, fortunately, it doesn't disappoint. Like its predecessor, SuperFreakonomics explores "the hidden side of everything." In this case, the roster of improbable topics includes the similarities between streetwalkers and department store Santas; the most effective ways to catch terrorists; whether eating kangaroos can save the planet; correlations between television viewing and crime; and whether we're hardwired for altruism and selfishness.