Logic-based representations of ontologies, and description logics in particular, have been of enormous benefit for the ontological community. The main advantage this approach has provided, is a clear formal semantics with efficient and practical reasoners. The growing popularity in the use of ontologies has identified the need for dealing in appropriate ways with changing ontologies. While some interesting and useful results have already been obtained, the approach so far has been somewhat ad hoc. In this talk I will argue that a systematic logic-based approach will have similar advantages for ontology dynamics than that brought about by the use of description logics in ontological representations. The approach I will focus is the body of work on Belief Change developed over the past 20-25 years.