In the practice of public health, the patient is the population rather than the individual; and actions and policies to promote public health therefore consider the welfare of the collective, often without regard for the interests of individuals. In liberal society, public health practice therefore exists in tension with constitutional law, judicial precedent, and even our culture itself, in which the individual is most often the unit of measure and analysis. In this course, we will consider the major categories of public health practice - including disease reporting and data collection, compelled treatment and vaccination, isolation and quarantine, inspection of public facilities and private homes, licensure of health professionals, regulation of food and drugs, environmental regulation, and sanitation - and their sources of legal authority and legal limitations. Public health will be viewed in historical perspective, and we will particularly examine the roots of modern public health practice in the nineteenth century work of Hermann Biggs and John Snow, and in the odd alignment of German public health practitioners with Nazi government efforts in the 1930s to control tobacco use and promote national health. Case examples will be drawn from recent public health controversies relating to the control of multi-drug resistant tuberculosis, HIV/AIDS, obesity, tobacco, and substance abuse.