In this book Ernest Sosa explains the nature of knowledge through an approach originated by him years ago known as virtue epistemology. Here he provides the first comprehensive account of his views on epistemic normativity as a form of performance normativity on two levels. On a first level is found the normativity of the apt performance whose success manifests the performer s competence. On a higher level is found the normativity of the meta-apt performance which manifests not necessarily first-order skill or competence but rather the reflective good judgment required for proper risk assessment. Sosa develops this bi-level account in multiple ways by applying it to issues much disputed in recent epistemology: epistemic agency how knowledge is normatively related to action the knowledge norm of assertion and the Meno problem as to how knowledge exceeds merely true belief. A full chapter is devoted to how experience should be understood if it is to figure in the epistemic competence that must be manifest in the truth of any belief apt enough to constitute knowledge. Another takes up the epistemology of testimony from the performance-theoretic perspective. Two other chapters are dedicated to comparisons with ostensibly rival views such as classical internalist foundationalism a knowledge-first view and attributor contextualism. The book concludes with a defense of the epistemic circularity inherent in meta-aptness and thereby in the full aptness of knowing full well.