When the recession of 1974 hit Wall Street, the investments profession desperately turned to the theories of a small and unlikely group of academics for guidance in finding a way to regain the value of their clients' holdings. Some of these scholars had begun to study stock prices merely as an expedient way to test the properties of large numbers, but inadvertently, they laid the intellectual foundation for a revolution in commerce. Peter L. Bernstein shows how Wall Street first fought, and then embraced, the advances wrought in the academic seminars and technical journals that ultimately transformed the art of investing.