Philosophers have for some time devoted their most systematic attention primarily to two large sets of questions, each of which develops out of concern with a pervasively compelling and troublesome aspect of our lives. In the first set, which constitutes the domain of epistemology, the questions derive in one way or another from our interest in deciding what to believe. The general topic of those in the second set is how to behave, insofar as this is the subject matter of ethics. It is also possible to delineate a third branch of inquiry, concerned with a cluster of questions which pertain to another thematic and fundamental preoccupation of human existence – namely, what to care about. It is not properly within the scope either of epistemology or of ethics to investigate the various distinctive conceptual questions to which this third preoccupation leads. Those disciplines need not reflect upon the nature of caring as such, nor are they obliged to consider what is implied by the fact that we are creatures to whom things matter. I shall not attempt to provide a formal and exhaustive account of the branch of inquiry that does specifically attend to such things. I propose in this essay merely to broach, in a somewhat tentative and fragmentary way, a few of its central concepts and issues. There is naturally an intimate connection between what a person cares about and what he will, generally or under certain conditions, think it best for himself to do.