This book describes the current status and results of photoelectron spectroscopic techniques, both theoretical and experimental, that have been applied to the study of the cuprate ("high-temperature") superconductors. The techniques described include angle-resolved photoelectron spectroscopy of valence electrons, core level spectra (XPS), and some special variations, such as resonance photoemission. Attention is paid to the difficulties in interpreting such spectra and to the problems obtaining good sample surfaces and high resolution, comparing results from other experimental techniques as well. The authors also outline expected future developments in the techniques. This book will be of great interest to graduate students and researchers in physics, chemistry and materials science with an interest in high temperature superconductors.