This article explores the evolution of Principles of Biomedical Ethics by Tom Beauchamp and James Childress over its seven editions. Many changes have occurred in the text over the last thirty-five years, including the expansion of the section on virtue ethics, the modification of the authors’ position on physician-assisted suicide, and the addition of many other ethical theories to the original two found in the first editions. The basis for these changes and others seems to be their development of the (...) theme of the “common morality.” The author suggests that Beauchamp and Childress develop the connection between their common morality and metaphysics, as it would serve to strengthen their theory and make it less susceptible to changes in society’s opinions and traditions. National Catholic Bioethics Quarterly 14.3 : 459–475. (shrink)