This study is part of a three-year ongoing IMLS-funded project on the research and development of FRBR-based retrieval systems to support user tasks and to facilitate effective information seeking. The major focus of this study is on user research and testing of current FRBR prototype systems. A sample of three such FRBR prototypes are evaluated and compared by 72 users from both public and academic library settings. This user study will help identify useful options for FRBR implementation and contribute toward the development of more effective FRBR systems in the future. The findings of this study will also reveal current FRBR implementation issues and possible solutions from users' perspectives.