Database documentation is provided for users of a data file consisting of a directory of all main public libraries in the United States. The directory development survey began with the mailing of a computer printout containing listings of each state's public libraries to the chief officer of the appropriate state library agency for updating. A…

Describes PLEXUS, an expert system for information retrieval related to gardening, designed at the University of London for use in public libraries. Focusing on the semantic problems encountered, methods used in artificial intelligence and information science to resolve them are discussed, including classification and facet analysis. (Author/LRW)