This monograph presents the latest results related to bio-mechanical systems and materials. The bio-mechanical systems with which his book is concerned are prostheses, implants, medical operation robots and muscular re-training systems. To characterize and design such systems, a multi-disciplinary approach is required which involves the classical disciplines of mechanical/materials engineering and biology and medicine. The challenge in such an approach is that views, concepts or even language are sometimes different from discipline to discipline and the interaction and communication of the scientists must be first developed and adjusted. Within the context of materials' science, the book covers the interaction of materials with mechanical systems, their description as a mechanical system or their mechanical properties.