It is a pleasure to present the book provides a comprehensive and up to date account of the EPR and Luminescence Studies on metal ions and rare earth doped glasses. This book has been written in a simple and lucid manner. The book only all inclusive dealing with EPR and optical studies. This book continues to be a resource for Optical Engineers, Researchers and Graduate Students. Every effort has been made to make the treatment simple and comprehensive. The topics are explained with the help of clear diagrams, S.I. units are used throughout the book. In spite of our best efforts, some errors might have crept. The authors do not take any legal responsibility for such errors and omissions.