This document discusses three case studies related to public health ethics and provides background information on relevant ethical principles and frameworks. The case studies involve: 1) a community health initiative on teenage pregnancy, 2) a proposal to strengthen laws against homelessness, and 3) the use of "sin taxes" to influence health behaviors. Background information is presented on ethical theories like egalitarianism, libertarianism, and theories of justice. Principles of public health ethics and frameworks for analyzing issues of social and economic justice are also defined.