Small sealed electrochemical power units have developed remarkably in the last two decades owing to improvements in technology and a greater understanding of the underlying basic sciences. These high-energy-density sealed battery sys­ tems have made possible the safe and rapid development of lightweight implant­ able electrical devices, some of which, such as heart pacers, have reached a large market. In most of these devices the battery constitutes the majority of the device volume and weight, and limits the useful life. This book on Batteries for Implantable Biomedical Devices will be highly welcome to those interested in devices for heart pacing, pain suppression, bone repair, bone fusion, heart assist, and diabetes control, as well as numerous other biomedical devices that depend on sealed batteries. However, the material will also be extremely useful to a much broader audience, including those concerned with sealed batteries for such other difficult environments as space, the sea and remote locations.