Dynamic Epistemic Logic

I will introduce various logics for change of knowledge and belief, that have become known under the name ‘Dynamic Epistemic Logic’. The basic logic of public announcements, proposed by Jan Plaza in 1989, serves to formalize logic puzzles such as ‘muddy children’, and ‘consecutive numbers’. But much more is possible in this setting, and there are generalizations to private actions, combining information change with factual change, and so on. I will point out some relations with AGM belief revision, with Moore-sentences (p is true and you don't know that p) and with knowability (is everything knowable? no!). The topic remains much in the limelight, latest developments are about protocols, and quantifying over information change, and protocol synthesis/planning. I will give a sprinkling of such topics as well.