Belief Revision (Belief Change) is the research field that makes use of tools and methods of formal logic to produce models of how human and artificial agents change their beliefs in response to new information. These models serve as a basis for understanding how beliefs can be changed, and how these changes can be regarded as rational. This is a multidisciplinary task, with applications to several areas including Formal Epistemology, Artificial Intelligence, Ontology, Databases, and many more.