This chapter presents the definitions, prevalence, prognosis, warning signs, and treatment for anorexia nervosa (AN), bulimia nervosa (BN), eating disorder not otherwise specified or atypical eating disorder (AED), and binge-eating disorder (BED). The distinctive core psychopathology for both anorexia nervosa (AN) and bulimia nervosa (BN) is a person’s constant concern and evaluation of his or her shape and weight. Psychological symptoms of AN include depression, anxiety disorder, irritability, mood swings, impaired concentration, loss of sexual desire, and obsessive thoughts. Some people who suffer with BN complain of stomach flu symptoms or complain that certain foods do not digest well. The distinguishing factor between BN and BED is the absence of compensatory purging in BED. BED shares the core eating disorder psychopathology, including preoccupation with shape and weight, the degree to which self-worth is influenced by weight, low self-esteem, poor social adjustment, and high rates of comorbid psychiatric disorders.