 Lewis is obviously not as well known for his work in ethics as for his work in other areas of philosophy. It was something of a surprise when one of the volumes of his collected papers was called Papers in Ethics and Social Philosophy (2000a). On the other hand, the existence of this volume indicates that there is a large body of work that Lewis put together in moral philosophy, very broadly construed. There is very little secondary literature on Lewis’s ethics. I’m drawing heavily here on chapter 8 of Nolan (2005), and Keller (2015).