XPath Help

Hi, I'm trying to get some XPath to work with respect to a navigation tree. <?xml version="1.0" encoding="utf-8" ?> <tree>   <node objectid="3456" title="Informationa">     <node objectid="2134" title="Contact" />     <node objectid="5656" title="Top 1.2" />     <node objectid="5672" title="Top 1.3" />     <node objectid="123" title="Top 1.4" />     <node objectid="8357" title="Top 1.5" />   </node>   <node objectid="9834" title="Banks" circuit="banks" />   <node objectid="2245" title="Corporates" circuit="corporates">     <node objectid="45688" title="Top 3.1" />     <node objectid="9567" title="Top 3.2" />     <node objectid="4633" title="Top 3.3" />   </node>   <node objectid="1554" title="Managers" />   <node objectid="6734" title="Library" /> </tree> I can use Xpath to return all the child nodes within a node using //node[@objectid="3"] However, how can I do this in reverse?  How can I retrieve the node that is the parent of a particular node?  How can I get the objectid of the parent of 2134? Any help you could share would be great! Thanks Tony