This volume brings together the collected contributions on the theme of robust mechanism design and robust implementation that Dirk Bergemann and Stephen Morris have been working on for the past decade. The collection is preceded by a comprehensive introductory essay, specifically written for this volume with the aim of providing the readers with an overview of the research agenda pursued in the collected papers. The introduction selectively presents the main results of the papers, and attempts to illustrate many of them in terms of a common and canonical example, namely a single unit auction with interdependent values. It is our hope that the use of this example facilitates the presentation of the results and that it brings the main insights within the context of an important economic mechanism, namely the generalized second price auction.