 On the one hand, there are questions about ability itself. The central question here to give an account of what an ability is, in the sense foregrounded at the outset. Subsidiary questions here include, for example, whether abilities may exist when they are unexercised, whether abilities are intrinsic or extrinsic features of their bearers, and whether agents have abilities in deterministic worlds. These are, broadly speaking, questions about the metaphysics of ability.