Since the 1970s, the U.S. economy has been sending more and more of its rewards to fewer and fewer people. Once seen as a global exemplar of egalitarianism and middle-class opportunity, America has become the most unequal of developed nations--a land where corporate leaders earn hundreds of times the pay of average workers, and the only population group growing faster than millionaires is the uninsured. Statistics aside, this quarte-century-long trend...