This text explains the subject of electrochemistry in clear, straightforward language for undergraduates and mature scientists who want to understand solutions at the molecular level. It takes full advantage of the advances in microscopy, computing power, and industrial applications in the quarter-century since the publication of the first edition. Such new techniques include scanning-tunnelling microscopy, which enables us to see atoms on electrodes; new computers capable of molecular dynamics calculations that are used in arriving at experimental values; and new room-temperature molten salts that make possible the long-postponed introduction of commercial electric cars. The advances in electrochemistry have necessitated a thorough rewriting of volume 2, which starts with two chapters that have been thoroughly revamped from the first edition. Transients, the electrochemical approach to measurement, have been given a whole chapter to themselves. The contributions of quantum chemists to electrochemistry have resulted in a new chapter on quantum-oriented electrochemistry, which is followed by new chapters on photoelectrochemistry, organoelectrochemistry, and environmental electrochemistry. Finally, the chapter on energy conversion and storage reflects the many advances in that technology. A completely new feature is the liberal supply of problem sets that give students the opportunity to reinforce the knowledge introduced in each chapter. Problem types represent three levels of difficulty: exercises for practice in the use of equations; somewhat more involved problems that relate the material to real-life situations; and more difficult micro-research problems, each of which may take around a day to solve.