Based on the author's lecture notes for a course on Physical Chemistry of Oxides at High Temperatures held at the Graduate School of the Tokyo Institute of Technology, this book examines the micromechanism of migration of ions and electronic defects contained in solid and liquid oxides at high temperature.The book is primarily designed for use as a graduate-level text and includes 150 problems for students. The emphasis is on introduction of simple theories for transport properties of oxides, which can be universally used at low and high temperatures, for various combinations of oxides.