Knowledge-first epistemology places knowledge at the normative core of epistemological affairs: on this approach, central epistemic phenomena are to be analyzed in terms of knowledge. This Element offers a defence of an integrated, naturalistic knowledge-first account of justified belief, reasons, evidence and defeat, permissible assertion and action, and the epistemic normativity of practical and theoretical reasoning. On this account, the epistemic is an independent normative domain organized around one central etiological epistemic function: generating knowledge. In turn, this epistemic function generates epistemic norms of proper functioning that constitute the epistemic domain, and govern moves in our epistemic practice, such as forming beliefs, asserting, and reasoning. This title is also available as Open Access on Cambridge Core.