consciously or not - to win recognition of our scientific status from other disciplines. If, after going through this book, the reader comes out with the feeling that this shadow price is not all shadow after all, we will have achieved one of our goals! Both the merits and defects of this book stem from the fact that we tried to pursue a different approach in the study of economics. This line of thought originates in the area of pattern recognition and machine learn­ ing. For the past two decades, a number of applied mathematicans, logicians, and engineers have systematically tried to mimic human intelli­ gence in one of its most important functions viz. that of identifying and recognizing patterns in an a priori unorganized and confusing environment.