This volume contains the proceedings of the Symposion on Shoulder Joint Replace ment held at the Kieler Yacht Club in conjunction with the 35th Annual Meeting of the Northwest German Orthopaedic Surgeons at Kiel in 1985. Since the advent of suitable implant materials hemiarthroplasty of the shoulder was explored in the 1950s; total shoulder joint replacement was first reported in 1971. As interest in solutions to problems of the shoulder is growing, it appeared timely to present to interested clinicians the possibilities and limitations of a proce dure as seen after nearly two decades of trials and experience. This volume is meant to give a comprehensive overview of the bases, the development, the alternatives, the state ofthe art and, an outlook on some future trends. The number of patients with problems warranting shoulder arthroplasty is rela tively small. We consider this a blessing. This may be the reason why the number of surgeons who ventured in this field has remained small, even after implants became available - testimony of an awareness, that shoulder surgery is difficult. The editors consider themselves fortunate to have been able to call on a number of those individuals, who were involved in first trials and in their evaluation. The editors are especially indebted to those from overseas who took it upon themselves to come, share their experience and join in the discussion.