This book is concerned with the developments of electrochemical systems for energy conversion and storage. It takes a pragmatic view of the devices developed and seeks to determine the chemical principles on which they operate. It covers the following topics galvanic cells (batteries), fuel cells and biofuel cells (microbial and enzymatic), photovoltaic and photogalvanic cells for solar energy conversion and electrochemical capacitors (supercapacitors).  In the spirit of looking to the future the book also covers solar fuel cells to reduce carbon footprints and also "naked electronics" - the revolutionary new concept of utilising body itself as the energy source for technological exploitation. Written in a clear, tutorial approach with case studies, fully solved examples and problems by a unique, naturally energetic and enthusiastic, dynamic and young authoring team, this book gives insight and understanding to this important and relevant topic.