With grants from the Council on Library Resources (CLR) and the Association of Research Libraries (ARL), New York University (NYU) Libraries conducted a study to assess user reactions to their online catalog, Bobcat (Bobst Library Computerized Catalog). In order to evaluate the effectiveness of NYU's catalog, to describe users' attitudes toward the system, and to assess users' stated levels of satisfaction relative to success, a three-part study was implemented: (1) the CLR Study attempted to assess the attitudes and perceptions of both users and non-users; (2) the NYU Study examined the search patterns and attitudes of both computer and card catalog users; and (3) the Interview Study attempted to describe the search process and identify problem areas for both computer and card catalog users. The library conducted 1,166 user surveys and 497 nonuser surveys at various sites from December 1983 through May 1984. This report begins with a review of previous public catalog research and then presents the four hypotheses developed and tested in this study. A detailed discussion of the research procedure includes sections on the survey instruments, data collection, the survey sample (library users and study sample), and data analysis. Commentary and statistical results from each of the studies follows. Appended materials, which constitute the major portion of the report, include a profile of the online catalog, the survey instruments, maps showing catalog locations and a description of the NYU libraries, and extensive analyses of the data for the CLR and NYU studies. (THC)