"Please do everything to save his life." It is always heard at any place where care is given, although it is not said in each and every situation. Nowadays, the doctor's decision about his or her patients has become a dilemma. Is it the doctor's duty to relieve pain and suffering even by taking the patient's life? Or should she or he respect human life and stand back, waiting for the nature to take its course? Some people argue that in certain circumstances killing someone to relieve his or her suffering should be considered as a mercy killing, while others believe that letting someone die naturally is a matter of respecting human life. This book presents a simplistic way of thinking in a very complicated debate. It is about euthanasia, a topic which has been generally ignored and, unfortunately, in many countries has been misused or neglected. In fact, this book will show the exact meaning of the term "mercy killing" and the various types that exist. It will also describe the attitudes of many countries and the beliefs of different religions, as well as medical and social views about euthanasia.