Is knowledge better than true belief? Socrates thought so. If he was right, and it is better to know than to believe, then how is that the case? Knowledge is generally considered to be some sort of justified true belief; so, is it justification that makes knowledge somehow better? These questions motivate this book (specifically whether justification can possibly account for a value unique to knowledge). The book begins by presenting the justificatory landscape-in particular, the features of and division between externalist justification and internalist justification. The first major challenge, the Swamping Problem, appears to fatally wound externalism while only damaging internalism. However, it becomes apparent that internalism qua internalism cannot exclusively account for knowledge's value. Throughout the book, externalism's importance to epistemology becomes apparent. This invites a reconsideration of the value of externalism, and the book concludes that knowledge's value can be substantiated by an appeal to externalist justification. This analysis can engage those new to epistemology and interest those looking into its future.