ExtensibleStylesheetLanguage (XSL) has these related components, XsltLanguage, XpathLanguage and XslFormattingObjects. See http://www.w3.org/TR/xsl/ for the 2001 rectified standard.
Taken from Dexx http://www.devx.com/getHelpOn/10MinuteSolution/20353 and other sources
The debate
Pro: http://www.xml.com/lpt/a/1999/04/holman/xsl.html
Con: http://www.xml.com/lpt/a/1999/05/xsl/xslconsidered_1.html
What is a set of good articles, pro and con that reflected 2006 views?