 There are many variations of these puzzles, some of which motivate logics that can handle more than just public communication. Restricting attention to the variations above, we note that a formal logic for reasoning about these puzzles must be able to represent various agents’ knowledge along with changes in this knowledge that are brought about as a result of public announcements. One important thing to note is that the announcements in the puzzles are all truthful and completely trustworthy: so that we can solve the puzzles, we tacitly assume (among other things) that everything that is announced is in fact true and that all agents accept the content of a public announcement without question. These assumptions are of course unrealistic in many everyday situations, and, to be sure, there are more sophisticated Dynamic Epistemic Logics that can address more complicated and nuanced attitudes agents may have with respect to the information they receive. Nevertheless, in an appropriately restricted situation, Public Announcement Logic provides a basic framework for reasoning about truthful, completely trustworthy public announcements. 