The renaissance of epistemology between the two world wars forms a bridge between early modern and contemporary philosophy of knowledge. This paper traces the resurgence of interest in epistemology at the turn of the century, as a reaction against the nineteenth-century development of Neo-Kantian and Neo-Hegelian idealism, through the interwar renaissance of epistemology, prompted by major advances in mathematics, logic, and physics, and its ultimate transformation from a theory of ideas and judgement into a theory of propositional attitudes, sentences, and meanings.