Moral theories can be distinguished, not only by the answers they give, but also by the questions they ask. Utilitarianism's central commitment is to the promotion of well-being, impartially considered. This commitment shapes utilitarianism in a number of ways. If scarce resources should be directed where they will best promote well-being, and if theoretical attention is a scarce resource, then moral theorists should focus on topics that are most important to the future promotion of well-being. A theme of this Element is that, as times change, the priorities (both practical and theoretical) of utilitarianism also change. Questions that were once theoretical curiosities move centre stage. And themes from earlier utilitarians that have become unfashionable may come to the fore again. Utilitarianism is a living tradition, not an abstract set of timeless principles or a purely historical artefact.