Utilitarianism is a moral theory that evaluates actions based on their consequences. It holds that an action is right if it maximizes happiness or well-being for the greatest number of people. The document discusses the classic formulations of utilitarianism by philosophers like Bentham, Mill, and others. It also analyzes two versions - act and rule utilitarianism. While utilitarianism provides a systematic approach, it is subject to criticisms around the difficulty of measuring consequences and its apparent justification of normally impermissible means to achieve good ends.