Increase in Demand:
Exponential growth in the volume of published information, increase in the number of users and availability of large number of online and C D - R OM bibliographic databases providing easy and timely access to published information, resulted in great increase in demand for the original documents. Parallelly, the declining library budgets, increasing costs of the publications made it difficult for the libraries to meet the information needs of their clients from their own collection. So, more and more libraries started relying on other libraries to supplement their collection to provide adequate service to their clients. Over the years, what was earlier known as Interlending, grew into a planned system of interlibrary cooperation which included not only sharing of resources but also sharing of other services like acquisition, classification, cataloguing, information services and many more. To facilitate such cooperation, a unified list of documentary resources resources of cooperating libraries, like Union Catalogues were compiled.
However, interlibrary resource sharing systems had their own limitations, such as problems of updating the union catalogues, extra interleading burden on large libraries, withdrawal of some cooperating libraries, etc To overcome these delivery centres, exclusively devoted to document delivery services was felt.