It should be emphasized that, in the successful use of the amputation prosthesis, alignment and fitting are of first importance. Materials and complex joint mechanisms are entirely secondary. Fitting of the prosthesis should be individual and should be carried out at the place of manufacture under the supervision of the attending surgeon, working in complete cooperation with the limb maker. Both surgeon and limb maker should possess a thorough understanding of the anatomical and physiological principles of limb-fitting as described here. Only by the practical application of such principles can the normal physiological gait be approached, and the amputee be enabled to use his prosthesis with the greatest efficiency and comfort, and without undue awkwardness or fatigue.