Musculoskeletal diseases are rapidly becoming a major health concern. The incidence of osteoarthritis, the most common arthritic disorder, is increasing steadily due to the graying of the world population. This disease is responsible of human life, a time in for significant morbidity, particularly in the second half which the quality of life is of primary importance. The aim of this publication is to bring to physicians and scientists a comprehensive overview of the field, from molecules to men. The direct costs related to osteoarthritis have been increasing steadily over the years and will soon be comparable to those of other major illnesses, such as cardiovascular diseases. This, of course, does not take into account all of the other costs related to the disease which often cannot be simply calculated in dollars and cents. There has been a great deal of renewed interest in osteoarthritis in the last few decades. This has been brought on by the need to improve our knowledge of all aspects of the disease, especially with regard to its etiopathogenesis and treatment. The most recent findings and developments on the structural, bio chemical, biomechanical and molecular changes observed in clinical and ex perimental osteoarthritis are presented in this book.