Journal article: This paper surveys the main models of strategic information transmission. First, we study cheap talk games, i.e., direct communication games in which messages are costless and unverifiable. Then, we analyze persuasion games, in which players' information is certifiable. Finally, we show in various settings how multiple stages of bilateral communication and delayed information certification may significantly expand the set of equilibrium outcomes, even if only one individual is privately informed. Several geometric equilibrium characterizations, examples and applications are examined along the paper.