This study demonstrates the economic value to state government and the public of investing in school readiness for just one more child at risk of academic failure in Detroit relative to Michigan as whole. Much of this value takes the form of savings. For example, children who attend preschool require less special education, repeat grades less, have fewer behavioral problems in school, graduate at a higher rate than others, and have less involvement in the very expensive criminal justice system as both juveniles and adults. As adults they earn higher incomes, contribute more in taxes, and are more likely to be employable and employed in the new economy. In these and other respects, school readiness saves money in the K-12 educational system, criminal justice system, and social welfare system.