Several years have passed since the first edition of this book was published. During this period, significant developments in the study of electron systems have taken place, especially in the areas ofhigh-Tc superconductivity and the quantized Hall effect. These developments, and such fascinating subjects as crystallization and the stability of matter are included in the second edition. Bardstown, KY A.Isiham June 1997 Preface to the First Edition The study of electronic properties reveals a common basis for a variety of sys­ tems, including gaseous plasmas, ionic solutions, metals, and semiconductors. This study started with one-electron properties in free space, as discussed in solid-state books. However, significant progress has been made recently in more realistic and complicated cases with interactions, confinements, impu­ rities, and fields. Moreover, the recent discoveries of the quantum Hall effect, high-Tc superconductors, and localization phenomena, along with the intr~ duction of low-dimensional materials have opened new areas and have led to a tremendous number of articles in existing journals and even new specialized journals. This book has been written to provide a new, comprehensive review on electronic properties in such diverse areas and materials.