 family document types are <abbr title="Extensible Markup Language">XML</abbr> based,
and ultimately are designed to work in conjunction with XML-based user agents.
The details of this family and its evolution are
discussed in more detail in the section on <a href="#future">Future
Directions</a>. </p>

<p>XHTML 1.0 (this specification) is the first document type in the XHTML
family. It is a reformulation of the three HTML 4.0 document types as
applications of XML 1.0 <a href="#ref-xml"> [XML]</a>. It is int