In many languages and in a range of circumstances, a pronominal element may appear in a position in which one might have expected to see a gap bound by a clause-peripheral element (in relative clauses, constituent questions, cleft constructions, and the like). Such elements (often, but not exclusively, personal pronouns) are known as resumptive elements. Since they are formally pronouns but serve many of the core semantic functions associated with movement constructions, the study of resumptive elements raises fundamental questions about the nature of movement, about the nature of anaphoric elements and relationships, and about the nature of the interaction between these two spheres. These questions have been the focus of a great deal of work, beginning especially in the middle 1970s; this chapter surveys that work – the questions that have been asked, the phenomena that have been discovered, and the current state of thinking about the relevant questions. Consideration of the theoretical questions is organized around the asking of three questions: (i) what are the properties of resumptive elements; (ii) in what ways do they share, or fail to share, properties of movement constructions (island phenomena, reconstruction effects); and (iii) in what ways do they share, or fail to share, properties of anaphoric elements and interactions? In recent years especially, the study of resumption has been enriched by a great deal of experimental work, aimed not only at establishing some basic properties of resumptive elements, but also at better understanding the mechanisms involved in their production and comprehension. The chapter ends with a consideration of that work and its implications. Here, the central question that emerges quickly is that of how theories of competence and theories of performance interact with one another.