SOMObject is the root class for all SOM classes. It defines the essential behavior common to all SOM objects. All user-defined SOM classes are derived, directly or indirectly, from this class. That is, every SOM class is a subclass of SOMObject or of some other class derived from SOMObject. SOMObject has no instance variables, thus objects that inherit from SOMObject incur no size increase. They do inherit a suite of methods that provide the behavior required of all SOM objects.