Introduction Digital libraries are promising to make an immense information universe available to users. Large volumes of multimedia data will flow through high speed communication networks to satisfy the requests placed by patrons in this virtual space where research will take place. However, availability does not automatically imply effortless access for every individual user or group of users. The volume, complexity and dynamism of the information managed by digital libraries pose significant problems in bridging the accessibility gap between users' needs and available resources. One approach to dealing with this accessibility gap has been the introduction of agents into the architecture of complex information systems.
Agents are autonomous or semi-autonomous processes that perform a well defined mission.
In this paper, though, the discussion is centered on user agents. The vigorous research being undertaken in the field of digital libraries generates both the need and the opportunity for considering user agents as the basis for an alternative style of human-computer interaction. The potential of agents for contributing to a more lively, personalized and cooperating environment for the user cannot be over-emphasized. The issues discussed below, however, pertain to user agents and deserve particular attention when considering this interaction style for a digital library. The user should readily visualize the availability and capabilities of existing agents in the library.