The paper SGML Concepts was delivered at the Aslib Electronics Group Conference in 1992 (long before XML existed). This presentation was an experience because it was not only the first, but the only one that was scheduled to last 90 minutes (and just after lunch too).
The abbreviation SGML stands for Standard Generalized Markup Language. Markup refers to adding style and formatting information to text prior to publication. It is a Standard because SGML has been accepted and published by the ISO, and is not owned by any manufacturer or software provider. It is Generalised because SGML is powerful and flexible, allowing it to be used in many applications. And it is a Language that embodies a specification for creation of a set of rules to define the structure of a document.
SGML has been designed to easily cross incompatible computer platforms, and its "open" nature allows for relatively simple access and manipulation of an SGML conforming document by both people and computers.
Above all, SGML proposed a new way of thinking about document creation and presentation, by shifting document style considerations to the publication process rather than the creation process. This is done by dividing the document into named, logical elements, to which any style can be later applied. A by-product of this approach is the effective creation of a flexible database, providing further access to the data for information retrieval or for re-publication.