 The Categories leads us to expect that the study of being in general (being qua being) will crucially involve the study of substance, and when we turn to the Metaphysics we are not disappointed. First, in Metaphysics Γ Aristotle argues in a new way for the ontological priority of substance; and then, in Books Ζ, Η, and Θ, he wrestles with the problem of what it is to be a substance. We will begin with Γ’s account of the central place of substance in the study of being qua being.