Utilitarianism is an excellent moral philosophy for an enlightened society and its theories of state and law. The declared goal of all actions is not the adherence to religious or other traditional intentions, but happiness: "the greatest happiness for the greatest number of people." The starting point lies in psychology, specifically in the human pursuit of happiness. This most British of philosophies relies on common sense like no other. However, utilitarianism is also a unique example of how outrageous the consequences of an apparent premise can be. The intellectual efforts of utilitarians to escape these partly absurd consequences are of unparalleled intellectual brilliance. This introduction provides an overview of the essential thoughts and criticisms of utilitarianism - from Bentham to the modern era.