Bernard Gert's classic work Morality, in which he argues his distinctive and comprehensive moral theory, is now in its sixth edition. Gert argues that morality is an informal system that does not provide answers to every moral question but does always limit the range of morally acceptable options and so explains why some moral questions cannot be resolved. Gert describes the two-step procedure that is used in moral decisions and judgments, and he shows that moral rules cannot be understood independently of the system in which they are embedded. Although his moral theory is sophisticated, it is presented with a clarity that will appeal to undergraduate and graduate students alike, as well as anyone with a general interest in applied ethics. In this new edition, Gert perfects the consistency of his views by presenting his argument in greater detail; he also revises the text in light of a critical book and two symposia dedicated to his theory that have surfaced since the book's last publication. This is the definitive edition to the work that has received so much attention and acclaim.