The author initially examines the challenges to ethics posed by relativism -- which holds that ethical principles are relative, varying among settings, groups, and persons -- and by egoism, which contends that people always do what pleases them or is in their own interest. The author presents arguments to defeat the contentions of both these challenges to ethics. He then proceeds to review the ethical theories that attempt to answer the question, "What should I do?" These consist of consequentialist theory, notably utilitarianism, which measures the ethics of a behavior by the nature of the consequences it produces, and non-consequentialist theories, which hold that ethical behavior is inherently correct, regardless of the consequences. The non-consequentialist theories discussed are naturalist theory, including natural law and natural rights theories, and deontological theory, as developed by Immanuel Kant. The concluding section of the paper returns to a consideration of the Socratic question: "How best is it to live?" The focus of this discussion is on "virtue ethics," which pertains to the qualities of a "good" person as he/she engages in daily conduct and relationships. The author notes that "virtue ethics" correctly brings people to the basic Socratic question of how best to live life as a daily enterprise, but it is flawed in its failure to give due consideration to the resolution of particular moral dilemmas. The author advises that the ethical enterprise must encompass both virtuous habits and correct choices when confronted by specific ethical challenges. 21 references