One of the major interpretative challenges faced by contemporary readers of Sellars is that he was a deeply systematic philosopher who never articulated a single definitive presentation of his system. Accordingly, scholars need to make sense on their own as to how Sellars’s system hangs together, which requires finding an acceptable place for each conceptual component. Why did Sellars seemingly not present his system itself? The solution to this problem lies by way of solving a second problem: why did Sellars wait until the late 1960s to begin publishing on Kant, when he was interested in writing on Kant as a student in Oxford in the 1930s? I shall argue that he could not begin publishing on Kant until he had developed his concepts of framework analysis and theory development. These innovations allowed Sellars to critically appropriate and innovate on Kant. On this basis I shall show that Sellars’s magnum opus Science and Metaphysics (subtitled ‘Variations on Kantian Themes’) is in fact Sellars’s presentation of his system.