Skip Sauer of Clemson University and Russ Roberts discuss the economics of Michael Lewis's Moneyball. Lewis claims that the Oakland As found an undervalued asset--the ability of a baseball player to draw a walk--and used that insight to succeed while spending less money than their rivals. Is it true? Sauer and Roberts try to answer that and other questions. How competitive is the baseball industry? Why do some baseball skills get more attention than others? Plus, new feature: Mailbag!