The aim of the conference was to hold a working discussion on problems essential to the building of thesauri, a uniform comprehension of which would make it possible to build them in a manner ensuring easier communication and exchange of information between information systems covering different ranges of subject matter, and using different languages. The conference discussed the way essential terms such as "thesaurus,""descriptor," and "ascriptor" would be handled. The fundamental elements of which thesauri should consist were also discussed and special stress as laid on methods of thesauri building, selecting and qualifying descriptors, their structure, and interrelations and determination. The conference discussed the building of monolingual thesauri and some problems of polylingual thesauri and debated the Unesco publication, "Guidelines for the Establishment and Development of Monolingual Scientific and Technical Thesauri for Information Retrieval: third draft." (Author/AB)