This chapter provides a brief introduction to and overview of the contents of the Handbook. Several issues are highlighted, including changes since the previous edition of this volume, namely, the revised Diagnostic and Statistical Manual (DSM-5); the research domain criteria (RDoC), and recent technological innovations such as Internet treatment and the use of virtual reality related to eating disorders. Chapters on selective eating, bariatric surgery, and cognitive remediation have also been added. Themes carried forward from the previous edition of the Handbook are presented in updated chapters reviewing etiological, maintenance, assessment, comorbidity, medical complications, and pharmacotherapy, as well as evidence-based prevention and treatment considerations.