Many voices in the Western and Christian tradition – biblical, classical, patristic, and early modern – are united in identifying a moral problem with luxury. Yet in an age of unprecedented affluence, no Christian theological work is being done on luxury. A contemporary analysis of the problem of luxury needs to overcome the tendency, in economic ethics and Christian critiques of consumerism, to treat economic problems primarily on the structural level of society. It would need to address luxury in terms of the day-to-day actions of buying and consumption, rooted in the virtues and vices of the moral agent acting in the marketplace. While the material for such a treatment is available within the historical Christian tradition, in a wide range of ecumenical sources, it has disappeared. A vital, contemporary recovery of this material cannot simply repeat prophetic criticisms of wealth, but must engage modern economics, recent philosophical ethics and its interest in the moral psychology of the virtues and of happiness, and contemporary theological conceptions of the significance of material things. The Problem with Luxury seeks to fill a serious gap in our reflection on the Christian life by offering such an informed yet pastorally-applicable analysis of luxury. The project will result in the development of a relevant, contemporary casuistry of consumption, guiding Christians to the moderation, civic responsibility, and service to the Kingdom that most Christian thinkers throughout history saw as endangered by the pursuit of luxury.