This issue of JNCA is dedicated to the topic of digital libraries. As guest editor, one of my goals was to try to give the reader a feeling for the breadth of topics that are being considered in the digital libraries area. This issue contains papers on extending SQL to support integrated queries on bibliographic and relational databases, software tools for enhancing information access, the use of agent-based user interfaces, system design based upon a Hyper-G server, the use of on-line resources for education, and lessons in very large scale scientific publishing. A second goal was to try to include papers having different perspectives from different parts of the world. This issue contains papers from the U.S., Germany, Mexico, Singapore and Japan. Each of the six papers provides insights on the impacts that digital libraries will have on our society.
In 'Integrated queries to existing bibliographic and structured databases', Lim and Lu discuss an approach to the unification of bibliographic and structured data for querying in digital libraries. By extending standard SQL with facilities for handling MARC format databases, they show how the bibliographic data model may be integrated with the relational model in a loosely-coupled manner that allows transparent queries to distributed databases on the Internet.
In 'experimental studies on software tools to enhance accessibility to information in digital libraries,' Sugimoto et al. describe five experiments involving user interface metaphors, information visualization, collaboration support systems, and multi-lingual browsers. The paper describes the need for intuitive information access tools for novice users of digital libraries.
In 'Agent services for users of digital libraries', Sanchez and Leggett discuss the potential of agent-based user interfaces as an alternative style for information access and interaction with digital libraries. A prototypical implementation of a distributed client-server architecture for agent services within a substantial digital library project is described. User agents are shown to have potential for bridging the gap between the user's information needs and the large, dynamic and complex information spaces of digital libraries.
In 'DogitaLS1: The Dortmund digital library system,' Tochtermann et al. present their design rationale for building digital library systems and describe an implementation based upon these concepts. The DogitaLS1 digital library system uses the Hyper-G second generation Internet information system as a storage substrate. The paper discusses experiences using Hyper-G as the underlying server technology for DogitaLS1 and compares results with other research projects.
In 'Creating an inquiry-based learning environment using the World Wide Web,' Alloway et al. describe their experiences using on-line resources to promote sustained inquiry in science classrooms. The paper provides a good example of educational uses of digital libraries and discusses shortcomings in current technologies. If we take a