Control of scientific information is increasingly at the center of legal and administrative disputes, raising questions of sovereignty and secrecy, of proprietary rights over research. Disputes originate from efforts to extend the right of access to data at an early stage of research, from demands for information that threaten confidentiality, from proprietary interests in competitive areas of research, and from government restrictions on the free exchange of scientific ideas. They reflect policy changes with respect to information disclosure, university-industry collaboration, patent rights, and national security. A review of diverse situations that have led to disputes and of efforts to negotiate principles for controlling intellectual property suggests the problems of establishing such principles in the context of the changing role of science.