Book excerpt: In 2015, the Institute of Medicine (USA) issued a report critical of the research effort and clinical care for ME/CFS (Myalgic Encephalomyelitis/Chronic Fatigue Syndrome) formerly known as Chronic Fatigue Syndrome (CFS) and Chronic Fatigue Immune Deficiency Syndrome (CFIDS). While worldwide investigation into the cause and nature of ME/CFS remains disproportionately small, and treatment remains symptomatic and controversial, modest research continues in all aspects of this disease: epidemiology, possible infectious origins and other triggers, possible involvement of genetics, metabolism, and microbiome, influence of co-morbid conditions, and more. Treatment of patients consists of providing symptomatic relief. Guidance in doing so is provided for the clinician. School-age children require not only treatment but, as revealed in a 25-year retrospective study, continued engagement with peers and social activity. This e-book explores the breadth and depth of current ME/CFS research and clinical care. Its impact for other chronic, complex illnesses should not be overlooked.