International migration is a critical issue in contemporary societies. Migration is at the centre of the ‘transnationalized social question’ located at the interstices between the Global South and the Global North (Faist T. The Transnationalized Social Question. Migration and the Politics of Social Inequalities in the Twenty-First Century. Oxford University Press, Oxford, 2019). Whilst irregular migration is problematised and criminalised in the Global North, in sending societies venturing abroad is often viewed as a dream or a hope, regardless of the legal framework in which this mobility and subsequent settlement occur, thus often giving the impression that migrants take the time spent in an irregular condition for granted. This introduction will outline the structure of this Reader, in which we hope to provide ample insight into the contentious theme of irregular migration by elaborating on its origins, the policies devised to deal with it, possible responses to it, the actors involved, and the agency of irregular migrants themselves. The Reader starts by highlighting the issue of irregular migration, discussing terminology, and providing estimates of the population involved.