The informal economy is huge: recent estimates have confirmed its importance in terms of employment and gross domestic product in many countries in the Global North and South. Over the years many attempts have been made to define and explain the informal economy. While the past approaches were essentially based on dichotomies, in recent years attention has shifted to the continuum between formal and informal economy and to informality's segmentation. Although knowledge about the informal economy has improved over the years, some dilemmas are still unresolved, and the relationship between informality and globalization processes seems to demand more empirical research in order to understand how informality works in different contexts.