Because the topmost class in the hierarchy is the Object class, everything below it is an object. Objects, to interact with each other, require their own actions, called methods. Those methods that encode actions needed by all objects belong to the Object class.
As methods of the top class, every other class in the hierarchy inherits them. For now, think of inheritance as the handing down of methods from a "parent" class--called a superclass--to all of its "descendent" classes--called subclasses. Finally, instances acquire methods from their classes. The Object class, then, is the topmost, or root class, of the class hierarchy. Any method created for the Object class is made available to every other class in the hierarchy. From the programmer's standpoint, this happens automatically; it is handled by the REXX language itself.