The interest for common use of machine readable bibliographic data and for their universal accessability is in constant growth. Definitions, current developments, functions and importance of three kinds of catalogues for library and information service have been represented. Problems and further developments of
- shared catalogues
- union catalogues
- centralized cataloguing,
where common use of information data is the most evident feature, have been discussed. Their convergent point - the authority file - has been determined. In the vision of future catalogues the author is anticipating that they are going to become even more useful, more operative and universal information tools as they are in the present state-of-art
