Harlem Children’s Zone (HCZ), an ambitious social experiment, combines community programs with charter schools. Will Dobbie and Roland G. Fryer Jr. provide the first empirical test of the causal impact of HCZ charters on educational outcomes. Various strategies suggest that the effects of attending an HCZ middle school are enough to close the black-white achievement gap in mathematics. The effects in elementary school are large enough to close the racial achievement gap in both mathematics and ELA.