In 1987 sociologist William Julius Wilson published his influential book The Truly Disadvantaged, which argued that the growing geographic concentration of poor minority families in urban areas contributed to high rates of crime, out-of-wedlock births, female-headed families, and welfare dependency. The exodus of black working- and middle-class families during the 1960s and 1970s from inner-city areas had adverse effects on the poor families left behind in high-poverty areas, Wilson suggested, by eliminating a “social buffer” that helped “keep alive the perception that education is meaningful, that steady employment is a viable alternative to welfare, and that family stability is the norm, not the exception” (p. 49). Our research on the U.S. Department of Housing and Urban Development’s (HUD) Moving to Opportunity (MTO) randomized mobility experiment raises questions about whether Wilson was right about the effects of concentrated poverty on the earnings, welfare receipt, or schooling outcomes of low-income families living in such areas. But MTO suggests concentrated poverty does have extremely important impacts on outcomes not emphasized so much by Wilson – such as physical and mental health.