In my dissertation I seek to provide an account of well-being that is wider in scope than other contemporary accounts, and has the power to play a much more substantial and fruitful role in moral theory. I will argue that contemporary discussions of well-being have construed well-being too narrowly, thereby stripping it of its capacity to play a much more fruitful role in moral theory. Once we develop a better understanding of well-being, we will realize that it can play a much more significant role in our ethical theorizing. To do this I will: (a) show that well-being can be understood to be much more closely tied to moral goodness or virtue than previously thought, (b) develop an account of well-being that can harmonize both subjective and objective elements that all ethical theorists find appealing.  A central claim that I defend is that well-being (or welfare) is not just one kind of value or consideration among others, but one that can be taken to unify other values that can be realized in a person's life, by providing their purpose and point. The reason why this has not been fully appreciated is that during their discussions of the very concept of well-being, philosophers have often assumed a particular substantive conception of well-being. (This is, I will argue, due to a deeper philosophical position that attempts to make a sharp division between morality and self-interest.) But well-being, as that in virtue of which a person's life goes better, when taken in its most general sense, is a very broad notion that leaves wide open what particular kinds of values constitute it. So while it is true that welfare or 'prudential' value is conceptually different from other kinds of value that can be realized in one's life' aesthetic, moral, or perfectionist' these values are constitutive of welfare; what is good for us will depend on the different ways in which these values enter our lives. Another important part of the dissertation will also be to address what is perhaps the most central issue concerning well-being' whether or not well-being is ultimately subjective or objective. My strategy will be to go through some of the standard accounts of well-being offered by both subjectivists and objectivists and argue that none of them are fully adequate. I will contend that both subjective and objective elements of well-being are constitutive of it. I will then attempt to develop a more plausible and satisfying account of well-being, a species of perfectionist or nature-fulfillment account, that integrates both subjective and objective components. Once we see that the life with highest well-being includes both subjective and objective components, we will have a picture of how an ideal human life would go. And once we keep this picture firmly on our minds, we will also be able to have a deeper appreciation for the kind of work that well-being can do within moral theory, by providing an intelligible aim as the formal object of practical reason.