The term CAD Framework has come to mean all of the underlying facilities provided to the CAD tool developer, the CAD system integrator and the end user (IC or system designer) which are necessary to facilitate their tasks. Broadly speaking, these three groups of people represent the users of the CAD Framework, each with their own needs and particular emphasis. This book presents a general discussion of the major components of a CAD Framework and their relationships to one another. Each area is then presented in more detail. A brief review of the state-of-the-art is presented. Since the approach taken to the development and enhancement of CAD frameworks has had more impact on their success or failure than any particular design decision, some observations on this topic are included in chapter nine: "Implementing a CAD Framework". Finally the influence of related disciplines and the ongoing software standards efforts on the area of CAD environments is reviewed.