 The core intuition motivating the Information-as-range stance, is that an informational state may be characterised by the range of possibilities or configurations that are compatible with the information available at that state. Acquiring new information corresponds to a reduction of that range, thus reducing uncertainty about the actual configuration of affairs. With this understanding, the setting of possible-world semantics for epistemic modal logics proves to be rewarding for the study of various semantic aspects of information. A prominent phenomenon here is information update, which may occur in both individual and social settings, due to the interaction between both agents and their environment via different types of epistemic actions. We will see that an epistemic action is any action that facilitates the flow of information, hence we will return to epistemic actions themselves throughout.