Functional somatic syndromes are defined as physical syndromes without an organic disease explanation, demonstrable structural changes, or established biochemical abnormalities. This book reviews the state of scientific and clinical understanding of the nine most common functional somatic syndromes. For each syndrome, expert authors provide a brief historical perspective, a current definition, a case presentation, confirmatory and contradictory research findings, a discussion of the leading pathogenetic hypotheses, and guidelines for diagnosis and treatment. Advice is given for the determination of disability of patients with these medically unexplained disorders, and both medical and psychiatric interventions are described. Stressing the importance of a sound therapeutic relationship as a basis for treatment, this is an invaluable resource for professionals in primary care and many other disciplines.