BEFORE INFORMATION PROFESSIONALS CAN BEGIN to improve existing services in research libraries, they need to understand the information work involved in the research processes of contemporary researchers. In the sciences, research is becoming more broadly based and collaborative and, increasingly, information, techniques, and tools are being imported and exported across disciplinary boundaries. This article examines the information practices and strategies used by interdisciplinary scientists as they perform ''boundary work.'' As researchers gather and disseminate information outside their core knowledge domains through personal networks, conferences, and the literature, they interact with objects, methods, people, and words. Much of their information work is devoted to probing and learning in new subject areas, and they often rely on intermediaries to help collect and translate material from unfamiliar territories. Libraries that wish to facilitate cross-disciplinary inquiry will need to design information environments that support learning, provide tools that function as ''boundary objects,'' and offer intermediary services that assist in the transfer and translation of information across scientific communities.