Twenty-seven categorical and topical reports by nationally preeminent scholars comprise this report, intended to provide background information for Congress in reauthorizing the Individuals with Disabilities Education Act (IDEA). An introductory synthesis addresses principles of the IDEA, evidence of the Law's effectiveness and the effectiveness of special education, promising practices, continuing barriers to their implementation, and recommendations for change. Categorical reports include: (1) "Learning Disabilities" (Don D. Deshler and Jean Schumaker); (2) "Mental Retardation" (Edward A. Polloway et al.); (3) "Serious Emotional Disabilities" (Lucille Eber and C. Michael Nelson); (4) "Severe and Multiple Disabilities" (Michael F. Giangreco and Martha E. Snell); (5) "Autism" (Glen Dunlap and Meme Eno-Hieneman); (6) "Physical Disabilities" (Sherwood J. Best and Gary A. Best); (7) "Special Health Care Needs" (Marilyn Ault); (8) "Visual Impairments" (Sandra Lewis); (9) "Hearing Impairments" (John Luckner); and (10) "Traumatic Brain Injuries" (Ron Savage). Topical reports include: (1) "Early Intervention and Part H" (Don Bailey et al.); (2) "Early Childhood Education" (Michael J. Guralnick); (3) "Least Restrictive Environment: Overview and Upper School" (Susan Brody Hasazi and Katharine Furney); (4) "Least Restrictive Environment: Early Childhood" (Samuel L. Odom); (5) "Least Restrictive Environment: Elementary and Middle School" (Kathleen Gee); (6) "Social Relationships" (Luanna H. Meyer); (7) "Self-Determination" (Michael Wehmeyer); (8) "Transition" (Frank R. Rusch); (9) "Supported Employment" (Paul Wehman and W. Grant Revell, Jr.); (10) "Minority Issues" (Vivian Correa et al.); (11) "Collaboration" (Jacqueline Thousand et al.); (12) "Parent-Professional Participation" (Thomas H. Powell and Patricia L. Graham); (13) "School Restructuring" (Margaret McLaughlin); (14) "School-Linked Services" (Wayne Sailor); (15) "Participatory Action Research" (Ann P. Turnbull and H. Rutherford Turnbull III); (16) "Positive Behavioral Support" (Robert H. Horner et al.); and (17) "Violence Prevention and School Safety" (Hill W. Walker). A brief description of the National Council on Disability is appended. (Individual papers contain references.) (DB)