Electro-enzymology and coenzyme regeneration are the subjects of this volume which are related to such important areas as enzymatic transformation, synthesis, analysis, biosensor, energy conversion etc. Electro-enzymology is an interdisciplinary field resulting from the fusion of electrochemistry and enzymology. Coenzyme regeneration is one of the most important key techniques for the future development in bioreactors. This book contains most of the new topics in these fields including the authors' original works such as bioelectrocatalysis with electroconductive membrane, electrochemical immunoassay, affinity chromatographic reactors etc. This book can also be considered as a comprehensive bibliographic review, which will provide the reader with a good bird's-eye view. The fundamental aspects followed by the applications are written in each chapter. This style of writing will help the reader to understand the subjects in electro-enzymology and coenzyme regeneration.