Essays on Rationalizability

Three essays on rationalizability are included in this thesis. The first one concerns the main attempt of this solution concept --- to capture strategic implications of the common certainty of rationality. I show that the attempt is achieved in a sense with some technical conditions. The second one provides two extensions of rationalizability: (1) to strategic implications of common p-belief of rationality and (2) to games with incomplete information. Finally I show the robustness of rationalizable sets for strategic form games with or without complete information.