Widely regarded as the definitive reference, this handbook brings together foremost authorities on posttraumatic stress disorder (PTSD). Diagnostic and conceptual issues are reviewed in depth. The volume examines the causes and mechanisms of PTSD on multiple levels, from psychological processes to genes and neurobiology. Risk and resilience processes are addressed across development and in specific populations. Contributors describe evidence-based assessment and treatment approaches as well as promising emerging interventions. The integrative concluding chapter identifies key unanswered questions with important implications for science and practice. New to This Edition *Reflects major research advances and the new diagnostic criteria in DSM-5. *Chapters on the dissociative subtype of PTSD, child assessment, couple and family therapies, and group treatments. *Chapters on research methods, Internet-based interventions, telemental health, and implementation of best practices. *Many new authors and extensively revised chapters.