Written by an international group of leading experts from both academia and industry, this is the first comprehensive book on the topic for 10 years. Taking into account the commercial interest in these systems and the scientific and technological developments over the past decade, all important materials and systems are covered, with several chapters devoted to topics of direct industrial relevance. The book starts by providing an introduction to the general principles of electrochemistry, the properties of electrochemical capacitors, and electrochemical characterization techniques. There follows a discussion of electrical double layer capacitors and pseudocapacitors, as well as the various electrolyte systems, before going on to cover modeling, the manufacture of industrial capacitors, constraints, testing, and reliability.