This course examines health, illness, and public health at the societal level from both scientific and ethical perspectives, with attention to local, comparative, and international contexts. It seeks to explain the spread of diseases and other public health problems across populations, including pandemics, cross-border health risks, social determinants of health, health inequalities, and issues of health care access, and raises questions about how different societies and health systems respond to these challenges. Emphasis will be placed on how scientific reasoning, epidemiology, public policy, and biotechnology are used in addressing public health problems in Hong Kong and in comparative international cases. The course also explores the roles of individuals, health care professionals, governments, and public institutions in promoting good health and well-being and in responding to public health crises. In this connection, individuals’ rights in general, patients’ rights in particular, and broader questions of social justice, human rights, and the common good will be discussed, together with moral issues concerning the allocation of public resources in public health care.