Although in widespread use in certain centers abroad, alternative bearing surfaces are currently in developmental or early clinical stage in the United States. There are numerous manufacturing, regulatory, scientific, and clinical issues that need to be carefully examined prior to the widespread introduction of these devices. Eighteen peer-reviewed papers written by members of industry, academia, clinical practice, and the regulatory and standards communities are presented in four sections: Wear Testing; Metal-on-Metal Bearings; Ceramic Bearings; and Alternative Polymeric Bearings. A useful volume for orthopaedic surgeons; biomaterials researchers; orthopaedic engineers, and orthopadic device manufacturers.