Throughout history, men have repeatedly made judgments regarding their own conduct and that of their fellow men. Some acts have been judged to be right or good, while other acts have been denounced as wrong or evil. Ethical judgment in medicine, as in other areas of life, is an attempt to distinguish between good and bad conduct.This book is based on three lectures given by the author. The first lecture was an address delivered to medical undergraduates at the National University of Singapore in 1995. The second was a Commonwealth Medical Association lecture delivered a decade ago. The third was a Singapore Medical Association lecture delivered in 1981.This volume, while emphasising the principles of medical ethics, has been kept simple and brief and will make insightful and interesting reading for both the professionals and the general public.