Synopsis Today our understanding of chemical bonding, molecular reactivities, and various other fundamental chemical problems rests heavily on our knowledge of the detailed behaviuor of electrons in atoms and molecules. This book describes in detail some of the basic principles, methods and results of quantum chemistry that lead to our understanding of electron behaviour. The basic aspects of inorganic chemistry are presented significantly in this book. Many applications and practical problems are described. The order of the techniques included in conventional and would be liked by students. The chapters have been arranged in a conventional way, as it may be easy for students to pass from one to another with continuity. A complete insight into this subject becomes possible only when the student understands the basic principles. The present book is self-sufficient.