This Article examines the No Child Left Behind Act, which may be the most important federal education law in our nation’s history. The Act is supposed to increase academic achievement in schools across the nation, raise the performance of disadvantaged students to the level of their more affluent counterparts, and attract qualified professionals to teach in every classroom. These goals are obviously laudable. As Professor Ryan explains, however, the Act creates incentives that actually work against their achievement. Specifically, the Act unintentionally encourages states to lower their academic standards, promotes school segregation and the pushing out of poor and minority students, and discourages good teachers from taking jobs in challenging classrooms. Should any or all of these effects occur, achieving the Act’s goals will be more difficult, not less. Professor Ryan goes on to suggest a solution, albeit a partial one, to the problems created by the No Child Left Behind Act. Rather than focus on absolute achievement levels as the basis for school accountability, Ryan argues that the federal government and states should focus on rates of growth. Doing so would not only give a more accurate picture of school quality, and thus provide a fairer basis for school accountability; it would also diminish or eliminate the perverse incentives created by the No Child Left Behind Act. The Article concludes with a brief discussion of what the No Child Left Behind Act can teach us about the proper role of the federal government in education law and policy.