Description: This special topic volume deals with the development of novel solid state electrocatalysts of a high performance to enhance the rates of the hydrogen or oxygen evolution. It contains a description of various types of metals, alloys and composites which have been obtained using electrodeposition in aqueous solutions that has been identified to be a technologically feasible and economically superior technique for the production of the porous electrodes. The goal was to produce papers that would be useful to both the novice and the expert in hydrogen technologies. This volume is intended to be useful to the materials scientist or electrochemist, student or profesional, who is planning studies of solid state electrocatalysts and who may have had little previous experience with electrochemical measurements. Such a reader will find an outline of basic theory and a discussion of experimental techniques and data analysis, with examples and appropriate references. It is hoped that the more advanced reader will also find this volume valuable as a review and summary of the literature up to the time of writing, with a discussion of current theoretical and experimental issues of research activity in the field of hydrogen energy.