This paper discusses the current resurgence of interest in authority files and describes the automated authority files of the National Library of Canada. Factors contributing to this interest in such files include cooperative programs between libraries, the development of international standards, and the impact of computer technology and telecommunications. An automated authority file can result in great savings in time and money, as well as maintaining file integrity while allowing flexibility for local usage. The National Library of Canada, which has always had manual authority files, currently uses a batch mode authority system. A pilot project online authority system, DOBIS (Dortmunder Bibliothekssystem), is now operating at the National Library and the Canada Institute of Scientific and Technical Information for the production of a union list of serials and for reference activities. Completion of the pilot program is expected in September of 1979 with expanded use of the system planned for the year's end. The DOBIS system has been designed to provide decentralized access to all catalogs and files; it is a fully integrated system incorporating cataloging, catalog search, circulation, acquisition, and information retrieval functions. (RAA)