This book provides easy-to-access, reliable, up-to-date information on the numerous advances in research, assessment, treatment, and service delivery for clinicians, academics, administrators and other mental health professionals. It examines issues surrounding intellectual and developmental disabilities in a real-world sociopolitical framework. In addition, the book summarizes the major domains and emerging subspecialties of this vast area into one useful reference and so offers a wide range of assessment and diagnostic tools and tactics, including cognitive and adaptive behavior assessments.