As part of a project which evaluated online public access catalogs (OPAC's) through analyses of library patrons' needs and perceptions, self-administered questionnaires were completed by library patrons who were OPAC users and non-users at nine academic and public libraries. Focus group interviews were conducted with OPAC users and non-users, as well as technical and public services library staff at six libraries (academic, public, and the Library of Congress). The survey concerned respondents' most recent OPAC search and included questions addressing their attitudes toward OPAC's and traditional library catalogs, and reasons for OPAC non-use. Comments in focus group interviews aided in the interpretation of survey responses and in reaching smaller groups. Research findings focused on five general areas: (1) demographic background of respondents; (2) OPAC searching; (3) transition from the traditional library catalog to the computer catalog; (4) OPAC features; and (5) user assistance for searching OPAC's. This report includes a 33-item reference list, 25 illustrations, 68 tables, and appendices providing user and non-user questionnaire results. (Author/LMM)