The two chapters of this part provide a general introduction to the scope of this book and to some of the methods used in it. Chapter 1 offers a broad overview of the methodology employed by economists to study economic issues and indi- cates how these methods have evolved over the past two centuries. Elements common to many of those methods are illustrated by the simple supply-demand model of price determination. The chapter concludes with a brief outline that shows how the various parts of the book fit together.