This book comprises 20 chapters contributed by experts and research workers, many of whom are recognized nationally as well as internationally in their respective fields. We express our sincere gratitude to the authors for their commitment in contributing the chapters as well as, in some cases, for their understanding, patience, and valuable advice. The overwhelming response of the contributing authors was catalytic in helping us to complete the task of publishing this book in time.

By Kamal Jaiswal and M.G. Ragunathan