The 17th Conference on the human thyroid addressed the problem of hypothyroidism. Thyroid hormone deficiency is one of the most common endocrine diseases, particularly affecting the elderly (over 60) and women. Furthermore, one of every 3500 newborns is affected by congenital hypothyroidism, making it the most common metabolic disease in infants. Insufficient thyroid hormone affects the entire organism and has effects on skin and hair, cardiac system and mental functions. In this book renowned scientists present new andrelevant results on the causes, clinical manifestations, diagnostics and therapy of hypothyroidism.