In the Transcendental Aesthetic of the Critique of Pure Reason, Kant famously claims that space is the a priori form of outer intuition (the 'Form Thesis'). Inspired by P. F. Strawson's discussion of it, a number of prominent contemporary philosophers have seen in this claim a brilliant and distinctly Kantian insight about the relationship between space and objective experience. Unfortunately, Kant commentators, whose job it is to determine the precise meaning of the Form Thesis, the nature of Kant's argument for it, and its relationship to Kant's claims about space later in the Critique (in particular, in the Transcendental Analytic), have made little progress in their efforts. As I argue, this is because they have failed to see that Kant's Form Thesis is part of a larger metaphysics of space and is only intelligible in terms of it. In my dissertation, I interpret Kant's Form Thesis in light of his (largely unexplored) views about the relationship between space and mutual interaction (which Kant calls 'community'), and about the ontological grounding of various spatial properties. I argue that Kant's Form Thesis is part of a rich metaphysics of space that combines realist and idealist elements, and that takes as its starting point a very general characterization of space as the ground of the possibility of the community of the things in it