This ninth volume in Group IV of the Landolt-Börnstein series considers and describes the electrochemical processes at the boundaries of electrodes and electrolytes. The book first presents a thorough overview on the field of electrochemistry, to impart a precise understanding of the involved systems, and secondly collects all relevant data of electrochemical systems as reported up to the present time. Each chapter offers introductory explanation, followed by concise data tables.