Irregular migration is one of the most discussed social and political issues in Western European countries since at least a century. It has caused divisive debates on security and control policies and on the strong and compelling link between the legal status of migrants and their inclusion in host societies. This issue aims to address empirical historical questions on this topic which interrogate the dichotomy opposing legal and illegal migration in Europe. Shifting legal conditions and uncertain resident status are common situations and usual everyday matters for many migrants nowadays as in past times. In order to catch these ambiguous status and changing social conditions this issue focus on an historical period, going from the immediate period after WWII up to the restriction policies of the mid-Seventies, which is usually neglected in illegal migration studies.