Angle-resolved photoemission has become an indispensable tool for solid state and surface physicists and chemists. This book covers the underlying phenomenology of the technique, reviews its application to existing problems, and discusses future applications. The book is particularly timely given the significant improvements in experimental and theoretical methodology which have recently been or soon will be attained, namely, ultrahigh resolution studies using improved sources of synchrotron radiation, quasiparticle interpretation of measured dispersion relations and spectra, in situ growth of novel materials, etc. The technique has been applied predominantly to understand materials for which the one-electron paradigm is a reasonable approximation. Most chapters discuss this type of experiment: 2D and 3D states in metals and semiconductors, extrinsic states induced by adsorption, etc. Applications of the technique to materials where electron correlation plays a comparable role to that of solid state hybridization, ferro- and antiferromagnets, high T c superconductors, etc. are rapidly growing in popularity. These areas are also discussed and a foundation is laid for further experiments in this direction. Almost all chapters contain comprehensive bibliographies and compendia of systems studied. The book has an extensive index which cross references applications and systems studied.