Collection as the first stage of retrieval

Assembling collections of library materials serves two different purposes:
1. preserving a copy of potentially useful material that might otherwhise be lost to present and future users in an archival role.
2. Arranging for copies of selected materials to be collected and housed locally for the greater convenience of local users is a logical role.
It is very significant characteristic of the use of books that it is very helpful to have copies stored locally, a point we shall examine further in considering the implications for collection development activity of change in the technical medium of library materials. The overwhelming preponderance of libraries collections, even of research libraries, serve the second, logistic purpose in the sense that most of the materials acquired also exist elsewhere in other copies in other libraries. Imagine how much different, smaller, and more economical libraries would be if only the archival role mattered, and just one or two copies were acquired nationwide or worldwide.
The assembling of a library collection, therefore, can reasonably be regarded as the first stage of the process of retrieving material for use. One might also argue that collections themselves serve as a form of bibliographic retrieval system analogue to the catalog in that by inspecting the array of books on the shelves one can discover works on perticular topics. Ordinarily “retrieval” is thought of only in term of catalogs, indexes, classification schemes, or other devices that provide pointers to the documents or dta that might satisfy the inquiries that arise. However it is important to recognize that, regardless of the terminology used, the archival role of library collections is, in an important sense, a necessary precondition for, or first stage of, retrieval-and the logistic role greatly facilitates convenient retrieval. Material that has not been collected at all is simply not available for retrieval by anyone. Material that has not been added to local collections is not available for convenient retrieval by individuals at that location. It is true that material that has not been collected locally can still be obtained by purchase, by reproduction, or by interlibrary loan, but all of these involve delay and expense and are best seen as procedures that are corrective of failures in collection development.