||Modal epistemology investigates the question: how do we know what is possible and what is necessary? Metaphysical modality is the main kind of modality that is investigated here. There are five main subquestions in the area: (i) The metaphysical question: what is metaphysical modality? What is it for something to be metaphysically necessary or possible? How is metaphysical modality related to logical and physical modality? (ii) The intentional question: how is that we can have beliefs about what is metaphysically necessary and metaphysically possible? (iii) The methodological question: what ways, if any, are there for forming reasonable beliefs and / or arriving at knowledge of metaphysical modality? (iv) The psychological question: what methods do we typically use in forming beliefs about metaphysical modality? (iv) The normative question: how should we go about forming and justifying beliefs about metaphysical modality? Some the leading theories are the following: (a) metaphysical modality is identical to logical modality, it is a priori accessible, and we can use conceivability as guide for forming beliefs about metaphysical modality. (b) metaphysical modality is identical to physical modality, it is neither a priori nor a posteriori, and we can use counterfactual reasoning in imagination to form beliefs about metaphysical modality. (c) metaphysical modality is neither reducible to logical nor physical modality, it is a priori accessible, but neither conceivability nor counterfactual reasoning is our basic guide. Rather, we come to know about metaphysical modality by reasoning from the essences of entities.