I first present a conception of the relata involved in the dialogic relation. I and thou are persons endowed with a first-person perspective and concepts through which they can represent themselves as distinct of anyone or anything else. Then I briefly discuss the epistemology and metaphysics of persons as agents. I adopt a realist view against any epistemological projects denying (or feigning to deny) the existence of the second person. Then I expose the complementary view of the secondperson perspective, which close the gap between the first- and third-person perspectives. I expose some historical milestones recognizing the importance of the second-person perspective in dialogue. After an examination of the conditions for the use of mental terms, I propose an analysis of dialogue in sequences of illocutionary acts, stressing the importance of perlocutionary plans. Any dialogue worthy of the name involves mutual understanding. In my reconstruction, I use distinctions proposed by Burge, Dummett and Austin. There are degrees of understanding in dialogue. In the highest degree, we have a real “meeting of minds.” Finally, a genuine dialogue is different from a fictional dialogue. I also suggest, taking side with Descartes, that the interaction man-machine cannot be classified as genuine dialogue.