In this article, different definitions of the term Digital Libraries are discussed. Two major definitions are dwelled upon: one emerging from the library world and the other from the world of scientific research. | We have, for example, the technical issues which include the problem with standards and protocols. To bring the distributed variety of digital resources and services together in a way that allow for integration and unified search, retrieval and presentation is a great challenge for the future. So is the problem of transferring personalised service and support from standard library and information services to the digital library. A user interface can hardly replace person to person service but better user interfaces must be developed and researched in order to help users. The future digital library will go beyond helping the user with searching and browsing only. They must be able to expect support for taking correct actions and getting help for problem solving where the digital library system confirm or deny existing hypotheses. In an interesting paper Feng et al.[Feng et al. 2005] distinguishes between traditional searching and browsing which is called “tactical level cognition” and the problem solving act which is called “strategic level cognition”. In the future, the authors argue, digital libraries must become not only a simple storage place but a place where knowledge is acquired, shared and multiplied. To facilitate the browsing function digital libraries must integrate diverse repositories of coherent collections and include navigation, searching and browsing facilities in a network of inter-related concepts and repositories. That takes care of the “tactical level cognition”. The “strategic level cognition” support must provide justifications and evidences by adding value and advocating a closer interaction between users and the content. To do this it is necessary to use some sort of vocabulary. Parallell to classic keyword-based indexes and knowledge-based index must be constructed. The authors outline a framework for a machine centered and extracted knowledge discovery across multiple repositories. This is being done in six steps by setting up knowledge discovery targets; identifying relevant resources; filter out interesting concepts; correlating concepts; extracting knowledge and justifications from correlated concepts and the evaluation of the same. It is one possible road ahead. But before we are there the solution to everyday problems like long term preservation of digital objects; copyright of digital material; good solutions for
