This comprehensive, interdisciplinary handbook presents the latest research in the study, assessment, treatment, and understanding of intellectual and developmental disabilities. The past five decades have resulted in dramatic breakthroughs in the understanding of intellectual and developmental disabilities (IDD). Editor-in-Chief Laraine Masters Glidden and her editorial team provide an overview of the historical foundations of the field of IDD as well as up-to-date material on clinical diagnosis, assessment, interventions, and treatments for such conditions. It goes on to address legal, ethical, and educational issues; and other social issues that affect the lives of people with IDD, including family impact and adjustment, relationships and parenting, spirituality, residential and caretaking services, maltreatment and criminal justice issues, stigma and ableism, health, and aging. Chapters address the etiology and treatment of specific conditions (including Down syndrome, fragile X syndrome, other genetic and chromosomal conditions, autism spectrum disorder, acquired brain injury, cerebral palsy, and fetal alcohol spectrum disorders) as well as functioning in multiple domains and throughout the lifespan. Contributing causes to IDD are explored within various contexts such as culture, race, ethnicity, and socioeconomic status.