In 1956, three groups independently reported evidence that some thyroid disease appearing spontaneously in humans or experimentally induced in animals are related to autoimmune processes. The interval between these landmark discoveries and the present has witnessed a remarkable and continuing growth of both knowledge and concepts concerning the mechanisms of immune regulation, the pathogenesis of autoimmune thyroid diseases, and their clinical and laboratory manifestations. More importantly knowledge of thyroid autoimmunity has, in many respects, comprised the vanguard of an ever increasing appreciation and understanding of autoimmune diseases in general. On November 24-26 1986, an International Symposium on Thyroid Autoimmunity was held in Pisa. Its purpose was to commemorate the birth of thyroid autoimmunity as a scientific discipline, to summarize current knowledge and concepts in this area, and where possible, to anticipate areas of opportunity for the future - hence the theme of the Symposium, Memories and Perspectives. To open the meeting, the Magnifico Rettore (Chancellor) of the University of Pisa granted special Awards to Dr. Deborah Doniach, Dr. Ivan Roitt, and Dr. Noel R. Rose, who published the first fundamental studies in the field of thyroid autoimmunity, and to Dr. Duncan G. Adams, whose discovery of the long-acting thyroid stimulator (LATS) opened the door to our current understanding of the pathogenesis of Graves'' disease. During the meeting thirty plenary lectures were presented.