The theme of this issue of the IEEE TCDL Bulletin illustrates an aspect of the breadth of the areas of specialization necessary for providing effective digital libraries. Digital libraries involve more than data more than the representation, storage, transmission, finding, and retrieval of information. Also necessary are user interfacesrequired if the library's patrons are to make use of the library's collection. The contributions in this issue provide glimpses into the issues and accomplishments associated with the broadly constituted topic of user interfaces for digital libraries.
Four distinctly different perspectives on digital library user interfaces are presented here. Certainly, many more are possible, indeed obvious. I hope that we will have the opportunity in a future issue of the Bulletin to visit some of these other user-interface-related aspects. The papers in this issue divide easily into three topic areas: the usability of digital library interfaces, engineering the generation of interfaces for new libraries, and innovative approaches to digital library user interfaces.
Ann Blandford and George Buchanan provide an overview of studies that have sought to influence, describe, and measure usability in digital libraries. A focus on usability moves discussion about a digital library's user interface from an enumeration of its features and "bells and whistles" to a consideration of its appropriateness and ease in achieving the goals of its patrons.
Ian Witten and his Greenstone project suggest the interesting possibility of separating collection from interface. Greenstone opens an avenue for developing the interface iteratively, beginning with a generic facility that, over time, becomes more precisely customized. In general, Greenstone focuses the digital library user interface design effort on the portions of the interface that need to be customized, saving the effort that otherwise would be required for re-implementing parts that can be handled in a standard manner.
The remaining two papers focus on novel user interface technologies as applied to digital libraries.
Thomas Phelps and Robert Wilensky describe the Multivalent Browser, which embodies a new metaphor for information presentation and manipulation. The result allows the reader great flexibility in determining the content's visualization.
The final paper in the issue is different in nature from the others, providing an overview of an ongoing series of workshops about applying computer visualization to digital libraries. Katy Börner and Chaomei Chen summarize the meetings, whose proceedings recently have appeared as a volume in Springer's Lecture Notes in Computer Science series.
Many of the areas in Computer Science and Information Science that are needed to develop digital libraries share the requirements of reflecting aspects of the collection, mediated by the characteristics of the available software, hardware, and network infrastructure. User interface design reflects, as well, the abilities and interests of the digital library's patrons its users. It is this connection with the patrons that is the distinguishing factor of this focus of investigation, ranging from design of the metaphors to be included in a library, through comparison of the design alternatives provided by the library's interface, to post-implementation evaluation that confirms the interface's strengths and weaknesses.