Brue’s Essentials Intellectual Disability is a concise, up-to-date overview of intellectual disability evaluation and assessment. This text offers a practical, concise overview of the nature of intellectual disability and adaptive skills functioning in children, adolescents, and adults. Coverage includes the latest information on prevalence, causes, differential diagnoses, behavioral and social concerns, test instruments, and the new DSM-5 diagnostic criteria. The discussion promotes a deeper understanding of the use of assessment data to inform interventions in clinical practice.