No Child Left Behind (NCLB) is a law that was passed by Congress, with strong support from both political parties. It is a somewhat complex law about federal support for education from kindergarten through 12th-grade (K-12). But the law's purposes are simple: to ensure that all children in the United States receive a high quality education and to close the achievement gap that exists between children who typically perform well in school and those who do not--many of whom are from minority racial and ethnic groups, have disabilities, live in poverty, or do not have English as their first language. The purpose of this document is to explain the benefits of NCLB.