Alasdair Chalmers MacIntyre is a Scottish-American philosopher who has contributed to moral and political philosophy as well as history of philosophy and theology. MacIntyre's After Virtue (1981) is one of the most important works of Anglophone moral and political philosophy in the 20th century. He is senior research fellow at the Centre for Contemporary Aristotelian Studies in Ethics and Politics (CASEP) at London Metropolitan University, emeritus Professor of Philosophy at the University of Notre Dame, and permanent senior distinguished research fellow at the Notre Dame Center for Ethics and Culture. During his lengthy academic career, he also taught at Brandeis University, Duke University, Vanderbilt University, and Boston University.

Ethics or moral philosophy is the philosophical study of moral phenomena. It investigates normative questions about what people ought to do or which behavior is morally right. It is usually divided into three major fields: normative ethics, applied ethics, and metaethics.