Leon Richard Kass, born on February 12, 1939, is an American physician, scientist, educator and public intellectual, best known as proponent of liberal education via the "Great Books", as an opponent of human cloning and euthanasia, as a critic of unrestrained technological progress and embryo research, and for his controversial tenure as chairman of the President's Council on Bioethics from 2001 to 2005. Although Kass is often referred to as a bioethicist, he eschews the term and refers to himself as "an old-fashioned humanist. A humanist is concerned broadly with all aspects of human life, not just the ethical."
Kass is currently the Addie Clark Harding Professor in the College and the Committee on Social Thought at the University of Chicago and the Hertog Fellow at the American Enterprise Institute.
His books include Toward A More Natural Science: Biology and Human Affairs, The Hungry Soul: Eating and the Perfecting of our Nature, Life, Liberty, and the Defense of Dignity: The Challenge for Bioethics, and The Beginning of Wisdom: Reading Genesis.