Hypertext Markup Language (HTML) has become ubiquitous in the last year through its association with the World-Wide Web. But HTML does not stand alone, it is just one document type definition of the Standard Generalized Markup Language (SGML), an international standard becoming more popular every day. SGML is used to produce both on-line and printed documentation. All O'Reilly books are composed in SGML and it is the basis of the Linux Documentation Project. As UNIX is to open systems, SGML is to portable documentation. At the UUASC March meeting, member Dave Close will outline the basics of SGML and explain why you should be using it to write your documents.