This introductory article argues that practices of professional thinking and acting on the presence of the immigrant offer a privileged analytical prism through which to study how post-WWII European welfare nation-states have been shaped and crafted. As such, study of the formation of post-WWII welfare nation-states where one usually does not look for them is suggested: that is, beyond the bureaucratic logic imposed by the state itself. Consequently, a wedge is driven into the mundane professional practices embedded in the immigrant/welfare nation-state nexus, through which may be observed the very heterogeneous production of problems and solutions with immense effect on human lives, communities, and societies. These practices demonstrate the boundary work of the welfare nation-state that shapes it and gives shape to the construction and reconstruction of immigrant children and their families as problems and, thus, objects of integration and professional intervention. In this sense, the prism offers a new approach to writing histories of immigrant children’s education and the shaping and crafting of welfare nation-states that displaces both objects of study to professional practices of their making. In the first part of the article, the privileging of this analytical prism is substantiated historically and theoretically. In the second part, the four contributions constituting this themed issue are introduced. Finally there is a discussion of how the four contributions demonstrate the analytical prism’s cross-national relevance and historical sensitivity, adding new histories of how immigrant children’s education has been caught up in the immigrant/welfare nation-state nexus.