On Mon, 05 Jul 1999 16:57:37 -0700, Michael Bernstein <mbernstein@profitscape.net> said: Michael> I want to create a set of Zclasses that can only be contained Michael> within certain other Zclasses. An arbitrary example would be a Michael> 'book' object that can only be created inside a 'shelf' object. Michael> I also would like to add a property to a ZClass that is a Michael> pointer to an instance of another ZClass of a certain type. An Michael> arbitrary example would be a 'Book' ZClass that has an 'Author' Michael> property that points to an instance of an 'Author' ZClass. Have you looked into using Object Manager as a base class? This allows specified types (including ZClasses) to be actually contained in your ZClass instances, kind of like a Folder. Alex Rice | alrice@swcp.com | http://www.swcp.com/~alrice Current Location: N. Rio Grande Bioregion, Southwestern USA