IMHO there are 7 markup languages that are commonly used: 1. HTML HTML is used for the WWW. Allows very simple formatting (such as bold, italic, underline, centre), and linking to other documents. 2. SGML SGML is a more generic markup language than HTML. Alongside SGML you need a document type definition (DTD) to specify the rules of that document's markup. So there is a DTD for HTML which specifies what tags can be used and what they achieve. Another common DTD for SGML is DocBook. DocBook is great - it specifies a lot more than HTML, including figures, table of contents, revision histories etc. 3. XML XML can be considered the successor to SGML. Again you have a template which specifies the rules for a document. For example Microsoft now have their own template, and there is also a template for DocBook. 4. Trof I don't know much about this other than it is the traditional Unix markup language. 5. RTF This is output by many word processors, but is surprisingly easy to write by hand. It is also an open standard unlike Word files. 6. LaTeX LaTeX is a set of macros to make TeX easier to use. It is great for writing reports and has great mathematical functionality. It is the only way that I know for a blind person to write printed maths. 7. Lout Lout is an attempt to make LaTeX more modern and easier to use, but it hasn't really taken off. In summary each of these methods has a set syntax for writing documents, and then you use a program to convert them to other formats like PDF, Postscript, ASCII, HTML and RTF. My personal preference goes to HTML for writing web pages (obviously), LaTeX for writing printed reports/assignments, and Docbook/XML for large documents to be published electronically. Hope this helps somewhat - I necessarily simplified a lot. Saqib
