Abstract
This paper studies the production of a reading discourse associated with the expansion and incipient professionalization of popular and worker's libraries during the first three decades of the 20th century. In the recovered documents, it is analyzed: the pedagogy of reading; the knowledge of the librarian space and its rules of use; the professionalization demands of the librarian. Among the main conclusions, the presence relations of difference and opposition between the participants of the field is verified.