In this classic of the Western philosophy John Stuart Mill tried to explain why utilitarianism is the best theory of ethics, and to defend it against a wide range of criticisms. Mill did that by presenting "the principle of utility" or "the greatest-happiness principle" and offering proofs for his theory. He argued various criticism argument by argument doing a great deal to popularize utilitarian ethic. His work is widely recognized today as "the most influential philosophical articulation of a liberal humanistic morality that was produced in the nineteenth century." Contents: • General Remarks • What Utilitarianism Is • Of the Ultimate Sanction of the Principle of Utility • Of What Sort of Proof the Principle of Utility Is Susceptible • Of the Connexion Between Justice and Utility