Manufacturing is evolving from an art or a trade into a science, an important one. A quarter of the population is involved in some form of manufacturing activity, and the rest of the population benefits from the products. When manufacturing was still an art, or rather a collection of very different arts, each had its own unique technology. Manufacturing is the conversion of naturally occurring raw materials into desired end-products. That manufacturing is indeed a monolithic function can be seen in its origins. Anthropologists suggest that one of the things that distinguished early man from other forms of life was the opposable thumb, which made it possible for a man to grasp and manipulate a tool. The purpose of the graphical model is to define and display the fundamental relationships of the many component functions which work together to accomplish manufacturing. The chapter also provides an overview of the key concepts discussed in this book.