The symposium will address two localized disorders of bone, Paget's disease of bone and fibrous dysplasia. Approximately 75% of the symposium will be devoted to Paget's disease and 25% to fibrous dysplasia. The Program Committee Co-Chairpersons are Drs. Ethel S. Siris and Frederick R. Singer. The Program Committee includes internationally recognized authorities on both disorders. Oral presentations will be from invited speakers and selected submitted abstracts. Abstracts not chosen for oral presentation will be presented as posters. Invited speakers will submit manuscripts that will be submitted to a medical journal for publication as a special supplement. The presentations will cover up to date information on the evaluation, treatment and etiology of the two disorders. The content of the symposium is designed to be of interest to both clinicians and other health professionals and to basic scientists who work in the area of bone biology. The learning objectives for symposium attendees are: 1.) to understand current thinking on the etiology and pathophysiology of the two disorders; 2.) to become aware of the most effective diagnostic tests to evaluate the two disorders; 3.) to appreciate the clinical manifestations and complications of the two disorders; 4.) to become aware of the effectiveness of the various drugs that can be used to treat the two disorders; 5.) to understand the role of surgery in managing the two disorders.