Now in an expanded and revised second edition, this book offers clear, penetrating examination of the central questions of ethics through study of the most important ethical theories in Western philosophy. Readers are introduced not only to the main ideas of each theory but also to contemporary developments and defenses of those ideas. Among theories the book covers are egoism, the eudaimonism of Plato and Aristotle, act and rule utilitarianism, modern natural law theory, Kant's moral theory, and existentialist ethics. Two new chapters add to this coverage expositions of Hume's ethics, Sidgwick's program for defending utilitarianism, and Rawls's hypothetical contractarianism. The discussions throughout draw the reader into philosophical inquiry through argument and criticism that illuminate the profundity of the questions under examination. Students will find this book to be a helpful guide to how philosophical inquiry is undertaken as well as to what the major theories of ethics hold.