 Dynamic Epistemic Logic is the study of modal logics of model change. DEL (pronounced “dell”) is a highly active area of applied logic that touches on topics in many areas, including Formal and Social Epistemology, Epistemic and Doxastic Logic, Belief Revision, multi-agent and distributed systems, Artificial Intelligence, Defeasible and Non-monotonic Reasoning, and Epistemic Game Theory. This article surveys DEL, identifying along the way a number of open questions and natural directions for further research.