Information Dynamics and Protocols Johan van Benthem, Jelle Gerbrandy, Tomohiro Hoshi, Eric Pacuit Abstract: We define new dynamic epistemic models with an added notion of 'protocol' describing the current informational process, which may reflect conversation, observation, or experiment. This adds a new concept of 'procedural information' to the factual and multi-agent information already handled by dynamic epistemic logics. We show how this richer perspective modifies existing representation results for DEL models inside branching temporal universes, and we give a new completeness proof for public announcement logic with protocols, which no longer works via the usual reduction to pure epistemic statements. Finally, we sketch the contours of a general logic of protocols. This is the expanded version of an earlier paper presented at TARK 2007, which includes a new notion of 'local' world-dependent protocols that need not be common knowledge between all agents involved. Keywords: Dynamic epistemic logic; Epistemic temporal logic; ; Protocols; Representation; Completeness