Abstract: An object-oriented interface is used to provide inheritance of object property information. A set of base object classes are created and stored in a persistent object state in non-volatile storage. A set of derived objects are then created using the base object classes and inherited base object property information. Derived object classes are saved in a persistent object state in non-volatile storage as a “delta” or difference between the derived object information and the inherited base object information. Saving only the derived class objects as a delta saves a significant amount of computer resources. When derived object is loaded, the base object class from which the derived object class inherited information is loaded first, then the derived object class delta is loaded. The two step loading process allows any changes made to the base object class to be automatically reflected in the derived object class by inheritance.