 In the previous section, we focused on one kind of model-transforming action: the public announcement. In this section, we look at the popular “action model” generalization of public announcements due to Baltag, Moss, and Solecki (Baltag, Moss, and Solecki 1998), together referred to as “BMS”. Action models are simple relational structures that can be used to describe a variety of informational actions, from public announcements to more subtle communications that may contain degrees of privacy, misdirection, deception, and suspicion, to name just a few possibilities. 