The Global Information Locator Service (GILS) encompasses a global vision framed by the fundamental values of open societies. Societal values such as a free flow of information impose certain requirements on the society's information infrastructure. These requirements in turn shape the various laws, policies, standards, and technologies that determine the infrastructure design. A particular focus of GILS is the requirement to provide the means for people to discover sources of data and information. Information discovery in the GILS vision is designed to be decentralized yet coherent, and globally comprehensive yet useful for detailed data. This article introduces basic concepts and design issues, with emphasis on the techniques by which GILS supports interoperability. It explains the practical implications of GILS for the common roles of organizations involved in handling information, from content provider through system engineer and intermediary to searcher. The article provides examples of GILS initiatives in various types of communities: bibliographic, geographic, environmental, and government. ?? 2001 Elsevier Science Inc.