Document Delivery Service:
The primary responsibility of the library is to provide the user with the texts (we may call them original documents). If the original documents are not available in the library, the librarian either borrows them from another library (inter-library loan) or obtains their photocopies. Although a precise definition of document delivery service is yet to emerge, we shall define it as the provision of documents by a library or information centre from its own resources or from some other sources. The document may be an original one or a copy thereof. Inter-library loan is one function of document delivery service which existed even in the late nineteenth century when the number of documents was not too large and the cost was also not prohibitive. The exponential growth of information, the ever increasing cost of documents, and cut-backs on library budgets as economy measureshad forced many libraries to realise that the development of self-sufficient library collections even inn a narrow discipline is an unattainable task. Besides, many libraries also need documents in peripheral subject areas. As a result, what was known as inter-library lending grew into a planned system of inter-library cooperation and to facilitate such cooperation, unified catalogues of