This book provides a broad introduction to an overview of developmental disabilities for future practitioners, educators, healthcare personnel, parents, and other lay people. Written in a manner accessible to all, this book presents a coherent picture of developmental disabilities by focusing on etiology (causes and risk factors), clinical phenomena, social factors, service delivery models, historical factors, and prevention. It stresses the revolution in services for persons with disabilities over the past few decades and emphasizes the importance of using a lifespan developmental model in service and research. For psychologists, educators, and special educators.