Recent research on Anorexia Nervosa and Bulimia Nervosa has yielded an increasingly detailed understanding of the range of biological and psychological abnormalities associated with these eating disorders. Inherited vulnerabilities, cultural pressures, and adverse individual and family experiences all appear to contribute to the onset of extreme dieting, binge eating, and purging. Once initiated, these behaviors give rise to multiple physiological disturbances, some of which may serve to perpetuate the illness. Although there have been substantial advances in the management of Bulimia Nervosa, the goal of offering effective treatment to all individuals with eating disorders remains elusive. This article reviews current thinking on the etiology and treatment of the two major eating disorders and a related syndrome, Binge Eating Disorder.