As its name implies, the Standard Generalized Markup Language standardizes the application of generalized markup concepts. SGML is not a markup scheme (that is, it does not prescribe a set of generic identifiers), but rather a methodology for creating such schemes. The language, which is based on IBM’s Document Composition Facility Generalized Markup Language, is being developed by the ISO, and has recently been published as an International Standard by that organization. Versions of SGML have already been implemented in several organizations or projects, including British Aerospace, and the New Oxford English Dictionary Project. The generic markup scheme under development as the Electronic Manuscript Project of the Association of American Publishers is also an SGML implementation. It should be noted, too, that Joan Smith of the National Computing Centre is a strong advocate of SGML.