Front Cover -- Defects in Two-Dimensional Materials -- Copyright -- Contents -- List of contributors -- About the editors -- Preface -- 1 Introduction -- References -- 2 Physics and theory of defects in 2D materials: the role of reduced dimensionality -- 2.1 Introduction -- 2.2 Classification of defects -- 2.3 Insights into the atomic structures of defects from scanning tunneling and transmission electron microscopy experiments -- 2.4 Production of defects in two-dimensional materials under electron and ion irradiation -- 2.5 Examples of defects in two-dimensional materials