In this review, Lorenzo Spagnesi analyses Marcus Willaschek’s new book on the Dialectic of Kant’s Critique of Pure Reason. In his book, Willaschek sets out to isolate and defend the constructive account of the Dialectic – what he calls the Rational Sources Account (RSA). On his reading, RSA states that metaphysical thinking arises from the very structure of human reason. The review presents the four levels of RSA and critically evaluates Willaschek’s interpretation