Abstract
The aim of this introductory article is to provide a critical overview of how informality has been defined and measured, together with selected findings on its extent and character, and a summary of competing views regarding its role in contemporary economies and how it can be tackled. The outcome is a set of conceptual frameworks for understanding both the burgeoning literature on informal employment and how each of the perspectives presented in this Special Issue contributes to the advancement of knowledge on this subject so as to set the scene for the articles that follow.