Bringing together electrochemistry, condensed matter physics and quantum chemistry, this book stresses basic theoretical ideas rather than experimental methods, and modern developments rather than traditional macroscopic concepts. Its unifying approach integrates the underlying conceptual framework of statistical mechanics, quantum theory of metals, kinetics, etc with the facts of electrochemistry. This approach reveals the true nature of the subject, which touches on so many fields. Topics covered include electrochemistry, thermodynamics and electrostatics, statistical mechanics, structure of surfaces, interfaces, theories of the hydrated electron, diffusion and more.