Online catalogs are types of interactive computer systems; they can also be called “interactive catalogs” because a user interacts with the computer to find relevant information. The interaction is the main difference between Online Public Access Catalogs (OPACs) and other types of library catalogs (Hildreth, 1982; Matthews, 1985). Online catalogs are regarded as real-time interactive retrieval systems for libraries (Fayen, 1983). According to Peters (1991), the development of online catalogs can be characterized by three decades of development. In the 1960s, the development of online catalogs was led by the development of computer technology and the library community’s desire to increase efficiency in finding library materials. In the 1970s, commercial vendors started to replace large university libraries as the principal developers of computer-based library systems. In the 1980s, local libraries expand their control of the library catalog systems.