> >>To store an external XML doc in a variable am I right in 
> saying I should 
> >>use document-node() ?
> >>
> >yes
> 
> So what advantage does document-node() give me over 
> element(), node(), or 
> item()??

It's more specific, and it therefore makes your code more robust. If you
write a function that's designed to process document nodes, and you call it
with an element node, then if the function signature says document-node()
you will get an error, but if it says node() then you won't.

Michael Kay
http://www.saxonica.com/