Dear Zopers In continuing my search for help it seems like ObjectManager is what I am looking for in order to have a large collection of different Python objects in the same folder allowing for many links among them. I will need to be able to select which kinds of items to show and sort them and use them in forms. That should be standard behaviour, though, I would expect. Do you happen to have experience with ObjectManager and/or have a good example that I can study? The application I am developing is for a musician who currently has an Excel sheet with more than 20.000 pieces of old music (1600-1900) where each PieceOfMusic object refers to other objects like Composer, OrchestralSetting, Instrument, Cast, Recording, Writer, etc. Those need to become different kinds of Python objects that the PieceOfMusic object can refer to in order to guarantee consistency. I have designed an object model with all the classes, their attributes and relations in a UML diagram, but now I need to convert the Excel sheet into Python objects in Zope and make them accessible through ZPT pages and Python methods based on this UML model. I assume that I need a class MusicLibrary that is a direct subclass of ObjectManager and a variety of classes that represent my application classes and are all subclasses of ObjectManagerItem. Do you agree with this? In the help about ObjectManager and ObjectManagerItem I miss a method like manage_addObject. There are only manage_self, manage_addProduct and manage_addFolder. But which method does the trick of adding Python objects to my product's folder? Any help is appreciated best wishes Andre Meyer