The concept of sales. The system-related nature of the sales area. In the modern economy, businesses fundamentally operate for external demand. They are therefore compelled to monetize the goods they produce or the services they provide for a fee. This performance monetization is the subject of the present second volume of the fundamentals of business administration. The first volume discussed the issues of performance creation and production. The third volume addresses the finances of companies. The term performance monetization is broader than the term sales, as sales strictly refers only to the disposal of goods and does not include the market monetization of services. Therefore, the term performance monetization would better characterize the subject of these investigations.