In the development of new CAD tools to be used in processing VLSI type circuits, the need for comprehensive models of electronic systems has become clear. This paper describes a model representation system in which a model, representing multiple views of a real system, at different levels of abstraction, can be constructed. Relationships that exist between different model types and levels of abstraction can be explicitly defined. Applications can, therefore, be decomposed into separate, well defined phases, each phase working with a model suited to it's task.