The DocBook Project
The DocBook Project supports the open-source development of a variety of DocBook resources; in particular, the DocBook XSL stylesheets.
DocBook provides a system for writing structured documents using SGML or XML. It is particularly well-suited to books and papers about computer hardware and software, though it is by no means limited to them.
In short, DocBook is an easy-to-understand and widely used DTD. Dozens of organizations use DocBook for millions of pages of documentation, in various print and online formats, worldwide.
(Look at the navigation in this website probably using ajax, it is facinating - ananth)
