We provide an overview of the design of PSI ("a Private data Sharing Interface"), a system we are developing to enable researchers in the social sciences and other fields to share and explore privacy-sensitive datasets with the strong privacy protections of differential privacy. * This work is part of the "Privacy Tools for Sharing Research Data" project at Harvard, supported by NSF grant CNS-1237235 and grants from the Sloan Foundation. This is a working paper describing a vision for work that is still in progress, and is therefore authored by the leadership of the efforts. Future and accompanying publications that emphasize specific technical contributions will be authored by team members responsible for those contributions.