ABSTRACT
This chapter aims to offer a guide for scholars from both political science and history to the study of informality. It conceptualises informality and discusses a variety of theories, methods and source types on which an analysis of the informal can be based. The chapter starts off with an overview of the dominating definitions of informality. It focuses notably on works from political science, since most existing conceptualisations of informality in European integration have been undertaken by scholars within that discipline. However, the chapter also builds on historical research concerning informal aspects in European integration: even though these studies rarely conceptualise the study of informality, they offer important insights for instance into the interplay of formal and informal processes, as well as with regard to source material when it comes to tracing the seemingly invisible. The chapter addresses various issues arising in the process of studying the informal, such as pitfalls in terms of available or unavailable data. Finally, the chapter offers some guidance on where to look for informality in European integration, and how to structure a research agenda accordingly.
