Ok, problem solved (mostly), more information and a lingering question. Voila! I noticed that the 1.7.5.2 xsl package I downloaded already includes a catalog.xml file http://docbook.sourceforge.net/release/xsl/1.75.2/catalog.xml So all I really need to do is link Oxygen's preferences to that specific catalog.xml file on my local machine. So, really, all I need to do is go to Preferences --> XML --> XML Catalog --> NEW Xml catalog --> Browse to catalog.xml in local xsl root (file:/I:/My%20Documents/xml/docbook-xsl-1.75.2/catalog.xml). When I right-click the href value and click Open File at Caret, it opens in the frameworks directory (not the path I gave it) to the default xsl file (which is 1.7.5.1). Humpf! If I change the xsl: import to <xsl:import href=" http://docbook.sourceforge.net/release/xsl/1.75.2/epub/docbook.xsl"/> and do the same thing, the correct file opens up in my editor. Horray! Although I've solved the problem, why didn't it work the first time? The catalog.xml file for the 1.7.5.1 looks pretty similar to the 1.7.5.2 one (although I noticed the absolute path for 1.7.5.2 is http://docbook.sourceforge.net/release/xsl/current/ but for 1.7.5.1 it's http://docbook.sourceforge.net/release/xsl-ns/current/ Any idea? Thanks. Robert ....................................................................... Hello, You should add the XML catalog of DocBook XSL 1.75.2 on the first position in the list of XML catalogs of the DocBook doctype that is available in Preferences -> Document Type Association. If you are a content author (you are not allowed to edit the document type) you have to duplicate the DocBook 4 or DocBook 5 document type and add I:\My Documents\xml\docbook-xsl-1.75.2\catalog.xml on the Catalogs tab of the dialog for editing the document type: http://www.oxygenxml.com/doc/ug-oxygen/dg-complex-customization-tutorial.htm... If your catalog is on the first position it will be parsed before the built-in catalog of Oxygen. You can check that the XML catalog is used by right click on the href value of <xsl:import href="http://docbook.sourceforge.net/release/xsl/current/epub/docbook.xsl"/> and run the action Open File at Caret. The action should open the stylesheet from I:\My Documents\xml\docbook-xsl-1.75.2. Regards, Sorin