How can we improve our ethical beliefs? How great are our capacities for moral improvement? What constitutes a good life? What role can philosophy play in answering these questions? In this important new book, one of our leading moral philosophers looks at central issues of ethics and emerges with the fullest and most elegant account of his fundamental ethical theory. James Griffin examines influential schools of ethical thought and finds deontology, virtue ethics, and most forms of utilitarianism to be overly ambitious. He argues that ethics cannot be what philosophers in these traditions expect because agents cannot be what the philosophies need them to be. Clear, compelling, and original, this new account of ethics will be of interest to anyone concerned with thinking about values: not only philosophers but legal, political, and economic theorists as well.