I'm stuck. I would like to build a "shiny new ZClass" that has the following structure: WebSimProduct WebSim Class 'Properties' Property Sheet string RunID Calc Class Object 'Properties' Property Sheet PathToInputFile PathToWxFolder Results Class Object 'Properties' Property Sheet float gashtg float elchtg float elcclg float euihtg float euiclg I haven't seen anything in the Zope documentation on using Zclass instances as members of a super class. In other programming languages I would instantiate default objects when the WebSim class is initialized. That way, to use a WebSim object, all I would need to do is instantiate one, then fill the properties of the automatiacally-created Calc object and Results object. However, I'm not sure how to build these default objects in Zope. My next question is: do I have to build a bunch of products (one for the Calc class and one for the Results class, for example)? I can imagine this would result in a huge number of products under the control panel if this is the case. I would like to have just a WebSim product and have all the other classes defined within this product. Does Zope work this way? If not, how is this class structure (or one similar) achieved? BTW, I've read, and disected to the best of my ability, the Zope Developer's Guide and the Searchable Job Board HowTo and Tazzzz'sss Adding ZClass Instances Programmatically and the Zope Content Manager's Guide 'Turining an Application into a Product.' However none of these deals with classes that contain custom class objects. Thanks for the guidance (TFTG?)! Eric.