The perovskite family of oxides includes a vast array of insulators, metals, and semiconductors. This is the first text devoted to a comprehensive theory of the solid-state properties of these fascinating materials. It includes complete descriptions of the important energy bands, photoemission, surface states, and the chapter on high-temperature superconductors explores the electronic states in typical copper-oxide materials. Theoretical results are compared to experiment and discussed throughout. With problem sets included, this is a unified, logical treatment of fundamental perovskite solid-state chemistry appealing to graduate students and researchers alike.