In “In Defense of Voluntary Euthanasia”, Sidney Hook describes his experience of being rejected to have a euthanasia that saves his life. However, he agrees to allow euthanasia for two reasons. First, as an old person, continuing treatment might cause other cardiovascular disease, makes the patients more painful. Second, he doesn’t want his family to go through this experience again. Moreover, he thinks a person who already has a satisficed lifetime “would be willing to accept the opportunity to be born again”. The author argues that legalizes euthanasia and uses it in a right way not only extricates the patients themselves but also their families. Furthermore, he asserts that mercy killing is also a “moral right”.