When it was passed in 1975, P.L. 94-142 guaranteed a free appropriate public education to each child with a disability. This law had a dramatic, positive impact on millions of children with disabilities in every state and each local community across the country.

The four purposes of the law articulated a compelling national mission to improve access to education for children with disabilities. (See sidebar: Four Purposes of P.L. 94-142.) Changes implicit in the law included efforts to (a) improve how children with disabilities were identified and educated, (b) evaluate the success of these efforts, and (c) provide due process protections for children and families. In addition, the law authorized financial incentives to enable states and localities to comply with P.L. 94-142.

P.L. 94-142 was a response to congressional concern for two groups of children. The law supported more than 1 million children with disabilities who had been excluded entirely from the education system. The law also supported children with disabilities who had had only limited access to the education system and were therefore denied an appropriate education. This latter group comprised more than half of all children with disabilities who were living in the United States in the early 1970s. These issues of improved access became guiding principles for further advances in educating children with disabilities over the last quarter of the 20th century.

Through such sustained federal leadership, the United States today is the world leader in early intervention and preschool programs for infants, toddlers, and preschool children with disabilities.