application of economic principles to decision-making in business firms or of other management units. The basic concepts are derived mainly from microeconomic theory, which studies the behaviour of individual consumers, firms, and industries, but new tools of analysis have been added. Statistical methods, for example, are becoming increasingly important in estimating current and future demand for products. The methods of operations research and programming provide scientific criteria for maximizing profit, minimizing cost, and selecting the most profitable combination of products. Decision-making theory and game theory, which recognize the conditions of uncertainty and imperfect knowledge under which business managers operate, have contributed to systematic methods of assessing investment opportunities.