> is it possible to use "external helper modules" within > an XSL document to perform specific processing? This is the subject of extension functions and extension elements, defined in section 14 of the August working draft: http://www.w3.org/TR/xslt#extension James Clark's XT is an XSL processor that implements the working draft using Java. I would point you to the extension function examples on his XT page at http://www.jclark.com/xml/xt.html but it seems to have gone missing! Michael Kay's SAXON is an XSL processor that implements extension functions in a similar, yet slightly different, way. http://users.iclway.co.uk/mhkay/saxon/ (read the XSL Conformance page).