Many commentators have suggested that economists in general and financial economists in particular have some responsibility for the recent global financial crisis. They were blinded by an irrational faith in a discredited Efficient Markets Hypothesis and failed to see the bubble in asset prices and to give due warning of its collapse. There is considerable confusion as to what this hypothesis is and what it says. The irony is that the strong implication of this hypothesis is that nobody, no practitioner, no academic and no regulator had the ability to foresee the collapse of this most recent bubble. While few economists believe it is literally true, this hypothesis is considered a useful benchmark with some important practical implications....