This paper explores the social shaping of network-based information systems, drawing on the author’s experience as a participant in a major networking project of the European Commission. The project was undertaken in conjunction with the establishment of a European Monitoring Centre for Drugs and Drug Addiction (EMCDDA). A key function of the EMCDDA is to integrate activities and sources of information (e.g., specialized libraries, documentation centres, statistical databases, etc.) dealing with drug abuse, i.e., possession or use of, or trafficking in illicit drugs. The social and technological complexities of building a trans-European network make it an especially interesting and revealing case to study. This paper examines in the ways in which the EMCDDA project has confronted and resolved the technological and social issues of network design and development.