Mark Timmons is Professor of Philosophy at the University of Arizona. He specializes in metaethics, Kant's ethics, and normative moral theory. He is author of Morality without Foundations (1999) and Moral Theory: An Introduction, 2nd edition (2013). A collection of his previously published articles on Kant's ethics are included in Significance and System: Essays on Kant's Ethics (2017). He is editor of Oxford Studies in Normative Ethics, and editor or co-editor of many volumes.