I haven't read your entire series yet (though I certainly intend to do so) but while scanning through this level it struck me you that you are referring to typed and untyped xml as if the difference would be that one has namespaces and the other hasn't. Forgive me if I have missed the essence of your writings by not reading it all yet, but I am pretty sure this is not the difference between the two. Instead 'untyped xml' is all xml text that is put into an xml variable/column declared as being of type 'xml'. It becomes 'typed xml' when the variable/column is validated against a schema by declaring the variable/column of type 'xml(CONTENT <schema collection name>)' or 'xml(DOCUMENT <schema collection name>)'