In 2008, a massive earthquake reduced the financial world to rubble. Standing in the smoke and ash, Alan Greenspan, the former chairman of the U.S. Federal Reserve once hailed as “the greatest banker who ever lived,” confessed to Congress that he was “shocked” that the markets did not operate according to his lifelong expectations. He had “made a mistake in presuming that the self-interest of organizations, specifically banks and others, was such that they were best capable of protecting their own shareholders.”

A version of this article appeared in the July–August 2009 issue of Harvard Business Review.