 Although recent interest in metaphysical explanation arose from a renewed interest in grounding over the mid to late twentieth century, grounding explanation is arguably not the only form that metaphysical explanation can take. This point was recognized as far back as Aristotle, who in the Organon and Metaphysics discusses metaphysical explanations that work by citing facts about “the what it was to be” of some target phenomenon (see, e.g., Posterior Analytics 83a7; Topics 141b35; and Metaphysics 1003b24, 1006a32, 1006b13), or what we would now call its essence. Like grounding, there is controversy over what essence is; unlike grounding, much less has been said about how essence and explanation are related and how what might be called essentialist explanations work. We can again stay somewhat neutral in saying that they typically work by citing (or perhaps just providing contextually relevant information about) part of what it is to be some phenomenon, in terms of some other phenomenon (e.g., Fine 2015 and Koslicki 2012).