African Americans and Latinos earn lower grades and drop out of college more often than whites or Asians. Yet thirty years after deliberate minority recruitment efforts began, we still don't know why. In The Shape of the River, William Bowen and Derek Bok documented the benefits of affirmative action for minority students, their communities, and the nation at large. But they also found that too many failed to achieve academic success. In The Source of the River, Douglas Massey and his colleagues investigate the roots of minority underperformance in selective colleges and...