This comparative study of three major online bibliographic systems is designed to provide assistance to library administrators in the assessment of the potential impact of such systems upon the operations of their libraries. A side by side arrangement of the text allows an overview of any specific characteristic under consideration. These characteristics are divided into several broad areas: (1) description, i.e., information on current services, access modes, characteristics of users, system startup, user support services, and general system information; (2) searchability aspects, including the file system indexing, provisions for quality and authority control, and the command language and formats utilized; (3) processes and products associated with online cataloging, acquisitions, and serials control; (4) applications to other library functions, e.g., circulation, reference, interlibrary loan, and management information; (5) financial and administrative considerations, i.e., charges and fees, contract obligations, and arrangements with regional networks; and (6) system administration. Also included for each system are a chronology of system events, descriptions of announced future developments, a selected bibliography of evaluative studies, and a bibliography of training aids and manuals. Additional information on the individual systems that is not directly comparable is provided in a number of appendices. (RAA)