In 1978, the International Organization for Standardization (ISO) established a massive standards development program called Open Systems Interconnection to establish an architecture and family of standards that would serve as the generic basis for compatibility among systems for information interchange. These standards remain fundamentally relevant to today’s systems. This chapter presents the perspective, concepts, and functions of the Reference Model for Open Systems Interconnection (OSI), defined in International Standard ISO 7498, and the structure of the comprehensive family of International Standards that have been established for distributed information systems.