This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book proposes novel analyses of the basing relation, new lines of argument for and objections against various analyses of the basing relation, arguments regarding what sorts of things can stand in basing relations, and interesting and important connections between the basing relation and various other issues in epistemology. It attempts to resolve an apparent tension between the causal theory of the basing relation and epistemic conservatism, the view that having a belief confers some positive epistemic status on the content of that belief. The book is concerned with positively characterizing the epistemic basing relation and criticizing extant accounts of it, including extant accounts of the relationship between epistemic basing and propositional and doxastic justification. It shows how epistemic basing interfaces with a particular way of thinking about rational support in cases of perceptual knowledge.