In 1968, the Kerner Commission Report concluded that the nation was "moving toward two societies, one black, one white--separate and unequal." Without major social changes, the Commission warned, the U.S. faced a "system of apartheid" in its major cities. Today, 50 years after the report was issued, that prediction characterizes most of the nation's large urban areas, where intensifying segregation and concentrated poverty have collided with disparities in school funding to reinforce educational inequality. While racial achievement gaps in education have remained stubbornly large, segregation has been increasing steadily, creating a growing number of apartheid schools that serve almost exclusively students of color from low-income families. These schools are often severely under-resourced, and they struggle to close academic gaps while underwriting the additional costs of addressing the effects of poverty--hunger, homelessness, and other traumas experienced by children and families in low-income communities. For all these reasons, research has found that the extent to which students attend schools with other students from low-income families is one of the strongest predictors of their achievement. These trends once again threaten the very fabric of the nation, as gaps in educational opportunity and attainment continue at a time when those without education are locked out of the knowledge-based economy. [This brief is drawn from a chapter on education in the United States in "Healing Our Divided Society: Investing in America Fifty Years After the Kerner Report," the update to the 1968 report commissioned by President Lyndon Johnson.]