The substitution of relatively abundant and cheap raw materials for scarce and expensive resources has since the Industrial Revolution helped the world satisfy its voracious appetite for material inputs and cope with the problem of resource deletion. Despite its importance, however, there is still much we need to learn about the substitution process. To what extent, for example, is substitution intertwined with technological change? How important are material prices in simulating substitution? How quickly can substitution normally take place? How does it affect our ability to forecast mineral consumption; to apply conventional economic principles in analyzing mineral markets; to constrain monopoly or oligopoly power in these markets; to alleviate mineral shortages? This report is a reprint of the first part of a study undertaken in the hope of providing some insights into such questions. It provides an overview or summary.