Presents a classification scheme for generations of online catalogs; discusses current online technologies and identifies deficiencies; and discusses enhancements that will take online catalogs into the next generation. Such enhancements will include increased access to information through user-system dialogue, automatic search aids, subject…

Describes the design and operation of a prototype online catalog; reviews research which evaluated the system in terms of types of searches and success rates; and offers suggestions for enhancing subject access, including automatic stemming, synonym tables and cross-reference lists, and relevance feedback mechanisms. (CLB)