The marketing concept says that a firm should focus all of its efforts on satisfying its customers, at a profit. This is really a a new philosophy of business, replacing a production-oriented philosophy which focused on organizing a firm's resources to make products and then selling them. The marketing concept calls for reorienting the firm's ways of doing things. Instead of trying to get customers to buy what the firm has produced, a marketing-oriented firm would try to sell what the customers want. The underlying principle of the marketing concept is that a firm should seek to meet the needs of customers, at a profit, rather than place its main emphasis on its own internal activities and utilization of its resources. These latter factors are also important, of course, but those who believe in the marketing concept feel that customers' needs should be the firm's primary focus and that resources should be organized to satisfy those needs. Give the customer what he needs--this may seem so obvious and logical that it is difficult to understand why the marketing concept is considered such a breakthrough. However, people haven't always done the logical and obvious. In a typical company, production men thought mainly about getting the product out. Accountants were only interested in balancing the books. Financial people were absorbed in the company's cash position. And salesmen were mainly concerned with getting orders. No one was particularly concerned with whether the whole system made sense. As long as the company made a profit, each department went merrily on its independent way, "doing its own thing." Unfortunately, they still do in the majority of companies today. Finding out customer's attitudes can avoid prejudices and stereotypes commonly found in the typical organization. The need for market research to avoid stereotypes can be dramatized by the following results from a large-scale survey of European adults: The average Frenchman uses almost twice as many cosmetics and beauty aids as his wife. The Germans and the French eat more spaghetti than the Italians. French and Italian housewives are not as interested in cooking as their counterparts in Luxembourg and Belgium. No firm can conduct its business successfully without trying to measure the actual size of markets, present and future. Quantitative measurements are essential for the analysis of market opportunity, the planning of marketing programs, and the control of marketing effort. The firm may make many measures of demand, varying in the level of product aggregation, the time dimension,a nd the space dimension.(ABSTRACT TRUNCATED AT 400 WORDS)