\section{Conclusions and Future Research}

Central to our view of digital libraries over networked information tokens is the value-added construction of
information artifacts  and their use in personalized information environments. The library processes of artifact
construction and use are enabled and supported by advanced binding and tracing environments which place substantial
demands on the linguistic and architectural requirements for digital libraries. Although languages and systems such as
Tycoon meet many of the requirements requested, there remains the practical problem of how to best organize and customize
the concrete software which implements such advanced environments for library process support.

On various occasions in this paper we mentioned already the similarity between digital libraries with information
artifacts and software libraries (e.g. \cite{Meyer90,Meyer94})  with generic software tokens and customized software artifacts
constructed for specific use.  Based on our initial experience we expect that much of the functionality of the binding
and tracing environments for information artifacts can also be used for the construction and use of the software
artifacts required by digital libraries. The first-class status of data, code and threads in Tycoon provides a promising
framework for such an approach.

On the technology level, we have a vested interest in the extension of our binding technology,  e.g., by the concept of
versioned bindings and by extended operations on structured collections of bindings.

The most relevant input, however, for the future development of digital libraries we expect from our cooperation with
potential user communities which have both the relevant library contents as well as the pragmatics of how to use them.
From their feedback we expect to gain the domain knowledge which is required to design and realize the adequate
abstractions for future digital libraries. 



  
