Reading and writing problems in school children has been the focus of a growing scientific interest regarding during the twentieth century. In search for definition, cause(s) and pedagogical interventions the subject is explored in medical, psychological and educational research. It is a field of knowledge characterized by scientific controversies and competing explanatory frames. In this article we approach the issue from a historic perspective. During the 20th century the development of compulsory schooling in Sweden three main periods can be discerned. Each is characterised by one specific explanatory framework dominating the educational policy discourse. These changing periods are related to both the increase of school participation during the first decades of the 20th century and the political ambitions associated with an education for all social classes. The politics of reading and writing problems mirrors a conflict not only about scholarly perspectives on reading and writing problems but also about the organization of welfare and system of education