The topic of intrinsic value is of fundamental importance for ethical theory. Many major moral theories recognize at least some prima facie duty to promote what is intrinsically valuable or good or to choose actions whose total consequences are intrinsically better than the total consequences of alternative actions. Furthermore, any account of what it is to lead a good human life would seem to require an account of what kinds of experiences and activities are good in themselves. In order to understand the nature of a good life or the requirement to promote what is intrinsically good or better, we must understand what it is for something to be intrinsically good or intrinsically better than something else. We must also appreciate what kinds of things have this type of value and how the patterns and relationships between various goods and evils can affect the intrinsic value of a life or an outcome. Philosophical reflection on these issues may lead us to wonder whether there can be knowledge or warranted belief about what kinds of things have intrinsic value and, if so, what is the source of that warrant. In other words, we may ask what, if anything, makes some of our beliefs about intrinsic value more reasonable than others. Such philosophical reflection may also lead us to wonder about the objects of moral belief and knowledge, how such things as moral facts and properties are related to “natural” or nonethical facts and properties. In these ways, philosophical thought about intrinsic value and its nature raises questions of moral epistemology and moral ontology.