This Recommendation | International Standard is an integral part of the ODP Reference Model. It contains a motivational overview of Open Distributed Processing (ODP), giving scoping, justification and explanation of key concepts, and an outline of the ODP architecture. It contains explanatory material on how this Reference Model is to be interpreted and applied by its users, who may include standards writers and architects of ODP systems. It also contains a categorization of required areas of standardization expressed in terms of the reference points for conformance identified in ITU-T Rec. X.903 | ISO/IEC10746-3.