Since the begin, documents classification in Libraries and Information Centers has been to organize it into collections, so that the items are grouped with a related within a commun subject in order to retrieval and facilitate the searching into a singular topic. The challenge to achieving this objective has been to combine the refer theoretical models structured more or less into a knowledge organization, and a pragmatic organization needs of specific collections. We presents in this issue a panoramic overview about features and evolution of these kinds of systems, from its origins to the transformations which have involved its adaptation to the technology changes, as a customer of an increasingly diverse information, and a users more heterogeneous.
LIBRARY CLASSIFICATION SYSTEMS / KNOWLEDGE ORGANIZATION / FACETED SYSTEMS / HIERARCHICAL SYSTEMS / INFORMATION SEARCHING / EXPLORATORY SEARCHING / ONLINE CATALOGS / WORLD WIDE WEB.