Kant’s Reform of Metaphysics challenges a widespread way of framing the Critique of Pure Reason, namely, the idea that Kant in this work first and foremost aimed to identify the conditions of possibility of experience and mathematical cognition. My book shifts the focus from Kant’s account of these conditions to his account of the conditions under which metaphysics – represented by the works of Leibniz, Wolff and their followers – can become a science. I argue that Kant aimed to determine these conditions in the Critique to prepare the ground for the elaboration of a comprehensive metaphysical system. While this system would not have suffered from the defects of the systems put forward by Wolff and Baumgarten, it would have been similar to the latter in important respects. In the Critique and later texts, Kant repeatedly announced his intention in this regard, but the plan never materialized. This contributed importantly to the tendency among commentators, from Kant’s own time onward, to regard the Critique as a self-standing investigation into the limits of human cognition.