This document provides an overview of utilitarianism and John Stuart Mill. It defines key concepts of utilitarianism such as the principle of utility, act versus rule utilitarianism, and the focus on consequences. It discusses challenges of utilitarian reasoning around cases like torture. It also provides background on the origins of utilitarianism with philosophers Jeremy Bentham and John Stuart Mill, and describes some of their views, including their focus on the greatest happiness of the greatest number.