An Introduction to Robust Mechanism Design brings together and presents a number of results on the theme of robust mechanism design and robust implementation that the authors have been working on in the past decade. This work examines the implications of relaxing the strong informational assumptions that drive much of the mechanism design literature. The objective is to provide the reader with an overview of the research agenda and present the main results of this research by illustrating it in terms of a common and canonical example — the single unit auction with interdependent values. In addition, the monograph includes an extended discussion on the role of alternative assumptions about type spaces in the authors' work. It also discusses the literature to explain the common logic of the informational robustness approach that unifies the work that is surveyed in this monograph.