I argue in this thesis that the topic of Immanuel Kant's Critique of Pure Reason is an epistemology of metaphysics. This has important consequences for how the argumentative structure of the work should be understood. While the Critique constitutes an indispensable part of Kant’s philosophy in general and his ethics in particular, it is doubtful whether it is fully successful as it stands. In a footnote to his Metaphysical Foundations of Natural Science Kant hints at an alternative argumentative strategy to establish the claims of the Critique, but he seems not to have developed this in the subsequent 2nd edition of the Critique. In this thesis I present a critical reconstruction of this alternative argumentative strategy applied to the central topics of the Transcendental Analytic. I claim that it is the aim of the Transcendental Analytic as a whole to provide a justification for the claim that pure concepts – Categories – are validly applied to objects of experience. Following Kant’s hint in the footnote to the Foundations, I argue that this can be established directly from an analysis of the forms of empirical judgements, and that claims about space and time as forms of intuition and considerations about the nature of human sensibility, are redundant. This reconstruction offers a profoundly Kantian, yet robustly realist way of resolving important philosophical problems.