Kant's Critique of Pure Reason, his main work of theoretical philosophy, frequently uses metaphors from law. In this first book-length study in English of Kant's legal metaphors and their role in the first Critique, Sofie Møller shows that they are central to Kant's account of reason. Through an analysis of the legal metaphors in their entirety, she demonstrates that Kant conceives of reason as having a structure mirroring that of a legal system in a natural right framework. Her study shows that Kant's aim is to make cognisers become similar to authorized judges within such a system, by proving the legitimacy of the laws and the conditions under which valid judgments can be pronounced. These elements consolidate her conclusion that reason's systematicity is legal systematicity.