Book excerpt: Solid state power sources have developed remarkably in the last three decades owing to improvements in technology and a greater understanding of the underlying basic sciences. In particular, a greater impetus has recently been placed in developing and commercializing small, lightweight, and highly energetic solid state power sources driven by demands from portable consumer electronics, medical technology, sensors, and electric vehicles. This comprehensive handbook features contributions by forerunners in the field of solid state power source technology from universities, research organizations, and industry. It is directed at the physicist, chemist, materials scientist, electrochemist, electrical engineer, science students, battery and capacitor technologists, and evaluators of present and future generations of power sources, as a reference text providing state-of-the-art reviews on solid state battery and capacitor technologies, and also insights into likely future developments in the field. The volume covers a comprehensive series of articles that deal with the fundamental aspects and experimental aspects of solid state power sources, an in-depth discussion on the state of the various technologies, and applications of these technologies. A description of the recent developments on solid state capacitor technology, and a comprehensive list of references in each and every article will help the reader with an encyclopedia of hidden information. The organization of the material has been carefully divided into thirty-one chapters to ensure that the handbook is thoroughly comprehensive and authoritative on the subject for the reader.