I am pleased to present my second book with the title "Pharmacology - A Stepping Stone". In this book I tried to present the basics and simple details of Pharmacology with special emphasis on Pharmacodynamics, that is mechanism of action of drugs. This book on drugs/medicines is for the B. Pharmacy, D. Pharmacy, Physiotherapy, Medical and Nursing students. This book is useful for a common non-technical person also, provided one should be interested in knowing about drugs/ medicines. I treat myself as a student of Pharmacology, who is still learning. By this book I tried to share my views. This is my humble request to the readers to send their valuable suggestions, so that I shall come out as a better student.