For various reasons, irregular migration has become a more frequent phenomenon during the last decades. Without going deeper into the globalising context of growing and changing migration tendencies in different parts of the world, it should be remarked that this topic is gaining attention. Until recently, there was only a limited amount of scientific evidence on irregular migration (with a focus on clandestine activities such as human trafficking and smuggling). But these days, in Western societies there are humanitarian and social problems related to the growth of this group, problems which have stimulated political discussion. This has subsequently led to scientific research on the subject. Irregular migrants have become visible in our everyday lives. They defend their rights in self-help groups, protest marches and hunger strikes and they are visible in the streets: we are all familiar with the salesman in the Pakistani night shop, the East-European or South-American cleaning lady in the hotel, the gipsy woman begging for money. These clichés provide prototypical examples of the role irregular migrants play in the public imagination. As a consequence of this situation, both politicians and scientists want to ‘grab hold’ of what is happening and to acquire an overview of the state of affairs. Predominantly short-term government-driven research is flourishing.