In a series of articles on library automation, this is the first one describing and analyzing the introduction of library automation in the National and University Library in Ljubljana and in other Slovene public libraries from the outset to 1977. It discusses the process of creating the professional basis, which enabled the subsequent application of new technologies in public library services in Slovenia, and describes the terms and conditions in which the first attempts of implementation of computer systems were carried out. It especially underlines the importance of a very high level of professional awareness of the Slovene librarians. They promoted consistent consideration of the international professional standards and trends in library automation field in spite of the unfavourable economic situation in the country of that time, when the restrictions in the allocation of funds also limited the possibilities for the development of the Slovene librarianship. Therefore, it was very significant to make the best use of all disposable resources - also very moderate potentials of new information technology - even though only a very limited number of the Slovene librarians had the access.