Includes a historical perspective on Chronic Fatigue Syndrome (CFS); epidemiology; clinical picture; evaluation of patients; patient management; etiologic theories; Public Health Service resources; fact sheet; resources for patients; overview of the CFS Research Program, NIAID, and NIAID/Johns Hopkins Hospital Study, which seeks volunteers; management strategies for CFS; the relationship between neurally mediated hypotension and CFS; and fibromyalgia and CFS: solving diagnostic and therapeutic dilemmas.