Justification, or at least ‘justification’, bulks large in recent epistemology. The view that knowledge consists of true-justified-belief has been prominent in this century, and the justification of belief has attracted considerable attention in its own right. But it is usually not at all clear just what an epistemologist means by ‘justified’, just what concept the term is used to express. An enormous amount of energy has gone into the attempt to specify conditions under which beliefs of one or another sort are justified; but relatively little has been done to explain what it is for a belief to be justified, what that is for which conditions are being sought. The most common procedure has been to proceed on the basis of a number of obvious cases of justified belief, without pausing to determine what property it is of which these cases are instances. Now even if there were some single determinate concept that all these theoriests have implicitly in mind, this procedure would be less than wholly satisfactory. For in the absence of an explicit account of the concept being applied, we lack the most fundamental basis for deciding between supposed intuitions and for evaluating proposed conditions of justification. And in any event, as philosophers we do not seek merely to speak the truth, but also to gain an explicit, reflective understanding of the matters with which we deal. We want to know not only when our beliefs are justified, but also what it is to enjoy that status. True, not every fundamental concept can be explicated, but we shall find that much can be done with this one.