There is an extensive body of literature addressing the concept of accountability, replete with overlapping definitions. This chapter introduces readers to this wide body of cross-disciplinary literature to provide a picture of areas of agreement and disagreement amongst theorists. Though accountability remains a contested concept, there is general agreement that accountability refers to a relational mechanism that can be analysed within the framework of the questions: who is accountable, to whom, for what, and how? One of the largest unresolved questions about accountability, as explored in this chapter, is whether it is simply a mechanical concept (ie a description of a mechanism with certain attributes) or more broadly reflects a value or ideal (ie the notion of being an accountable person). The conclusion drawn here is that it is particularly difficult to divorce the concept of accountability from a normative background in discussing concepts of accountability deficits and overloads. Each of these concepts rests on the normative assumption that it is possible to identity an ‘ideal amount’ of accountability.