This chapter talks about comorbidity, aetiology, clinical conceptualisations, and assessment and management of four eating disorders: anorexia nervosa, bulimia nervosa, binge-eating disorder, and obesity. The classification systems of eating disorders according to Diagnostic and Statistical Manual of Mental Disorders (DSM)-IV and the 10th revision of the International Classification of Diseases (ICD-10) are also presented in the chapter. Eating disorders expanded from the historical accounts, which were of restricting anorexia nervosa to include a variety of disorders typified by the binge-eating disorders. A systematic review of the epidemiology of eating disorders concluded that the prevalence of bulimic disorders varies according to time and place. Many of the risk factors for bulimia nervosa are shared by people with binge-eating disorder although they may be less intense. The outcome of community ascertained binge eating disorder in terms of abnormal eating behaviour is better than that reported for bulimia nervosa.