I think I backed myself into a little corner. I've got a directory with multiple DTML documents. They do not all have the same set of properties. I can pull the entire list fine, but everything that I have tried to do to select objects with a specific property fails on all of the DTML documents that do not have that property defined. I have been unable to find something equivalent to an 'if exists' type dtml tag which will check for the existence of a property without trying to check for a non-existent property value first. I am assuming that this is not rocket science but a mental block on my part. Any assistance would be appreciated ... the code snippet is included with the troubling line that I need ... <TABLE ALIGN="CENTER"> <dtml-tree branches_expr="objectValues(['DTML Document'])"> <dtml-if "AUTHENTICATED_USER.has_permission('View',REQUEST)"> ==> <dtml-how do I check if the property exists "StaffLastName"> <==== <tr><td><A HREF="<dtml-var absolute_url>"> <IMG SRC="<dtml-var icon>" BORDER=0></a></td> <td><dtml-var title_or_id></td> </dtml-if> </dtml-if> </dtml-tree> </TABLE> As a tangent, is there a way to define a new objectValue type within a Zope product without writing python source?