Do epistemic requirements vary along with facts about what promotes agents' well-being? Epistemic instrumentalists say 'yes', and thereby earn a lot of contempt. This contempt is a mistake on two counts. First, it is incorrectly based: the reasons typically given for it are misguided. Second, it fails to distinguish between first- and second-order epistemic instrumentalism; and, it happens, only the former is contemptible. In this book, Nathaniel P. Sharadin argues for rejecting epistemic instrumentalism as a first-order view not because it suffers extensional failures, but because it suffers explanatory ones. By contrast, he argues that epistemic instrumentalism offers a natural, straightforward explanation of why being epistemically correct matters. What emerges is a second-order instrumentalist explanation for epistemic authority that is neutral between competing first-order epistemic theories. This neutrality is an advantage. But, drawing on work from cognitive science and psychology, Sharadin argues that instrumentalists can abandon that neutrality in order to adopt a view he calls epistemic ecologism. Epistemic Instrumentalism Explained will be of interest to researchers and advanced students working in epistemology, ethics, and philosophy of mind.