The Individuals with Disabilities Education Act (IDEA) is a law that makes available a free appropriate public education to eligible children with disabilities throughout the nation and ensures special education and related services to those children. The IDEA governs how states and public agencies provide early intervention, special education, and related services to more than 8 million (as of school year 2022-23) eligible infants, toddlers, children, and youth with disabilities. The stated purpose of the IDEA is: to ensure that all children with disabilities have available to them a free appropriate public education that emphasizes special education and related services designed to meet their unique needs and prepare them for further education, employment, and independent living; to ensure that the rights of children with disabilities and parents of such children are protected; to assist States, localities, educational service agencies, and Federal agencies to provide for the education of all children with disabilities; to assist States in the implementation of a statewide, comprehensive, coordinated, multidisciplinary, interagency system of early intervention services for infants and toddlers with disabilities and their families; to ensure that educators and parents have the necessary tools to improve educational results for children with disabilities by supporting system improvement activities; coordinated research and personnel preparation; coordinated technical assistance, dissemination, and support; and technology development and media services; to assess, and ensure the effectiveness of, efforts to educate children with disabilities. This book reviews the implementation and effectiveness of the IDEA.