Modern libraries are complex systems that consist of many procedures and functions. Traditionally, these functions (subsystems) have included acquisition of materials, cataloging and classification, circulation and interlibrary loan, serials management, and reference services. The most important function, however, has been the provision of service to the users. For centuries, librarians have managed warehouses of documents by acquiring, cataloging, and classifying books, journals, and other materials, and circulating them to their clients. Computer and telecommunication technologies have empowered the new breed of information professionals to select, organize, retrieve, and transfer (SORT) the actual information effectively and efficiently to the users.

In the Beginning

Historically, the most labor-intensive operation of a library has been circulation, the main goal of which is to retain a record for each item that is borrowed from the library. This transaction record usually contains information about the material (e.g., call number, title...