Relationship to Libraries:
Document collection is a major function of all information service units. Libraries are traditionally known to be centres for collecting and storing documents. For that matter, documentation and information centres were established initially as extensions of special libraries. This has been particularly so in our country where the documentation and information centres came up around the nucleus of special libraries. Most of the library practices and techniques are extended and refined to suit documentation and information work. Usually, documentation and information centres are set up in specialised subject fields for the benefit of specialist groups of users working in those fields. Initially, when information work was manual or semi-automatic in nature, it was possible for only special libraries to perform the task and meet the requirements. Besides, the size of both their user community and their collection was relatively small. Thus, special libraries easily and quickly became information centres.