Argues that Heidegger considers all three elements of his own view of the ‘concept and method’ of philosophy – ontology, phenomenology, and hermeneutics – to be at work in Kant’s Critique of Pure Reason. First, Heidegger's well-known ‘ontological reading’ of this work more specifically interprets it as a treatise on the possibility of general ontology (3.1). Further, he understands Kant’s critical approach as an attempt at developing the phenomenological method that such an ontology requires (3.2). Ultimately and most audaciously, Heidegger interprets the changes between the two editions of the first Critique as the result of Kant’s hermeneutical reflection upon this attempt (3.3). This chapter puts forward a new reading of Kant and the Problem of Metaphysics (GA 3) and Phenomenological Interpretation of Kant's Critique of Pure Reason (GA 25), but also draws from What is a Thing? (GA 41), Logic: The Question of Truth (GA 21), and Einleitung in die Philosophie (GA 27).