1,2 Spectroelectrochemistry (SEC) is a powerful yet usually inexpensive technique which yields mechanistic ( -chemistry ), energy-relevant ( -electro- ) as well as electronic structure information ( spectro- ). The whole range of the electromagnetic spectrum can be employed, from X-ray absorption to NMR spectroscopies. SEC is used in areas such as analytical, materials, supramolecular, surface, polymer, organic, organometallic, inorganic and bio-chemistry. The principles of the method and practical guidelines are presented here by relevant examples and this book will appeal to scientists from all chemical sub-fields who have a basic understanding and experience in electrochemistry. ...neverthless the book can be recommended for libraries of research institutions where basic spectroscopic tools are employed in these areas of chemistry. Wolfgang Kaim is currently at the University of Stuttgart. His background and qualifications are in physical organometallic chemistry of main group and transition elements and his research interests are in redox reactions, including biomimetic systems. Axel Klein is at the University of Koln and his research interests include the design of transition metal complexes for various purposes such as (electro)catalysis, luminescence, or photochemistry and the investigation of highly reactive intermediatesElectrochemistry affects several relevant research subjects of physics, chemistry and biology such as the transformation of materials, the transfer of information (especially in living systems), or the conversion and storage of energy. In addition, electrochemical processes constitute a major class of chemical reactions both in the laboratory and on large industrial scales. While conventional analytical electrochemistry provides excellent methods to determine concentrations (e.g. in sensor technology), to yield energy data in the form of redox potentials and to elucidate formal reaction mechanisms via kinetic analysis, these techniques alonelsH