This book is not a conventional reader in moral philosophy. To capture the essentials of what we know about the origins and nature of ethics, Peter Singer has drawn on anthropology, history, observation of non-human animals, the theory of evolution, game theory, and works of fiction, in addition to moral philosophy. By choosing some of the finest pieces of writing, old and new, in and about ethics, he conveys the intellectual excitement of the search for basic questions about how we ought to live.