diff --git a/src/guide/xml/ch04.xml b/src/guide/xml/ch04.xml
index 3dcb7bc16..8de93a3af 100644
--- a/src/guide/xml/ch04.xml
+++ b/src/guide/xml/ch04.xml
@@ -610,6 +610,13 @@ attribute to the root element (if it doesn’t already have one).
If it isn’t preserved, relative references to other documents will be resolved against
the static base URI of the stylesheet and not the URI of the original document. That’s
unlikely to be correct.
+You must also take into account that no XInclude processing has taken place at this time.
+If you are using modular DocBook, the transform-original pipeline is usually a bad choice,
+because it only operates on the root document, but not on the fragments referenced by XInclude.
+If it is absolutely necessary to use a transform-original pipeline together with modular DocBook,
+you can use Saxons -x
switch to enable XInclude when parsing the document (see ).
+Otherwise, however, the transform-before pipeline is usually the better choice
+for modular DocBook documentsModular DocBookprocessing pipelines.