Eating disorders are serious mental health disorders that are associated with significant morbidity and mortality. This chapter provides eating disorders clinicians with the necessary understanding of both the differences associated with specific ED diagnoses and the transdiagnostic features that commonly present across diagnoses. Many, if not all, of the common features can be targeted using exposure therapy, which is discussed in subsequent chapters. The authors specifically address the most common features of anorexia nervosa, bulimia nervosa, and binge-eating disorder, as well as avoidant/restrictive food intake disorder and other specified/unspecified eating disorders. Key transdiagnostic features of eating disorders, including eating-related fear and avoidance, body image disturbance, and binge eating, are addressed through a brief case study.