 In what follows, the discussion will roughly follow the historical development, starting with the attempts to give a modal-existential analysis of ontological dependence in  §2.  As we will see in  §2.2,  these attempts do have some serious shortcomings, even if they can be of use especially in certain restricted contexts. In  §3,  we see that there are important cases where a more fine-grained, asymmetric notion of explanatory dependence seems warranted. We will then proceed to the essentialist analysis of dependence in  §4,  a discussion of the relationship between metaphysical grounding and dependence in  §5,  finishing with a brief discussion of various other connections and applications in  §6.