The author discusses games of both perfect and imperfect information at two levels of structural detail: players' local actions, and their global powers for determining outcomes of the game. Matching logical languages are proposed for both. In particular, at the "action level", imperfect information games naturally model a combined "dynamic-epistemic language"--and correspondences are found between special axioms in this language and particular modes of playing games with their information dynamics. At the "outcome level", the paper presents suitable notions of game equivalence, and some simple representation results. Copyright 2001 by Blackwell Publishing Ltd and the Board of Trustees of the Bulletin of Economic Research
