The paper proves Paul Ladewig's thesis "The librarian must be able to do more than the teacher: to be able to teach, not to teach.." with examples of the activities of Czechoslovak librarians in the period 1918-1938. Czechoslovak public librarianship at this time was influenced by Anglo-Saxon models in the field of adult education, both in terms of the legislative framework and the activities and initiatives of individual librarians and their associations. In the introduction, the paper discusses the role of the Czechoslovak state in defining the field of adult education. The main part then will focus and analysis of specific examples of these activities in the practice of public libraries of the time, with emphasis on the role, influence and results of the work of selected Czechoslovak librarians.The paper also focuses marginally on non-state institutions that were involved in out-of-school education of adolescents and adults in the Czechoslovakia during this period.