Offering a comprehensive introduction to equilibrium electrochemistry, this primer deals with electrode potentials and their applications. It builds on a knowledge of elementary thermodynamics, giving the reader an appreciation of the origin of electrode potentials and shows how these are used to deduce a wealth of chemically important information such as equilibrium constants, free energy, enthalpy and entrophy changes of chemical reactions, activity coefficients, and the selective sensing of ions. The emphasis throughout is on understanding the foundations of the subject and how it may be used to study problems of chemical interest. The authors have minimized the mathematical aspects of the subject without any sacrifices in clarity, so as to enhance the accessibility of this volume.