diff --git a/Doc/lib/markup.tex b/Doc/lib/markup.tex
index 66934c42bd2..0d923a72d11 100644
--- a/Doc/lib/markup.tex
+++ b/Doc/lib/markup.tex
@@ -7,4 +7,23 @@ Standard Generalized Markup Language (SGML) and the Hypertext Markup
 Language (HTML), and several interfaces for working with the
 Extensible Markup Language (XML).
 
+It is important to note that modules in the \module{xml} package
+require that there be at least one SAX-compliant XML parser available.
+Starting with Python 2.3, the Expat parser is included with Python, so
+the \refmodule{xml.parsers.expat} module will always be available.
+You may still want to be aware of the \ulink{PyXML add-on
+package}{http://pyxml.sourceforge.net/}; that package provides an
+extended set of XML libraries for Python.
+
+The documentation for the \module{xml.dom} and \module{xml.sax}
+packages are the definition of the Python bindings for the DOM and SAX
+interfaces.
+
 \localmoduletable
+
+\begin{seealso}
+  \seetitle[http://pyxml.sourceforge.net/]
+           {Python/XML Libraries}
+           {Home page for the PyXML package, containing an extension
+            of \module{xml} package bundled with Python.}
+\end{seealso}