"The major divide in contemporary epistemology is between those who embrace and those who reject the a priori-knowledge that is independent of experience. The importance of this issue, however, extends beyond the boundaries of epistemology to include virtually every other area of philosophy. To a large extent, a philosopher's position on the a priori determines how he or she goes about answering other philosophical questions. Proponents of the a priori frequently allege that rejecting the a priori is tantamount to rejecting philosophy as a respectable intellectual discipline. Opponents respond that no intellectually respectable theory of knowledge can accommodate the a priori. Casullo's goal here is to provide a systematic treatment of the primary epistemological issues associated with the a priori, which is also sensitive to recent developments in the field. He points out that assessing the status of the a priori within contemporary epistemology requires distinguishing the requirements of the a priori from traditional assumptions about the nature of knowledge and justification. In freeing the a priori from these assumptions, he generates three major insights: First, the concept of a priori justification is minimal: it is simply the concept of non-experiential justification. Second, the basic question that must be addressed is whether there are non-experiential sources of justified beliefs. Third, and most importantly, articulating the concept of non-experiential justification and establishing that there are non-experiential sources of justified belief requires empirical investigation. Casullo argues that epistemologists should recognize the role that empirical evidence plays inresolving these fundamental issues. He concludes by proposing that traditional approaches to the a priori, which focus primarily on the concepts of necessity and analyticity, are misguided and essentially limited. Compelling and original, A Priori Justification should generate a reassessment of these fundamental questions among scholars interested in the theory of knowledge."