This chapter examines some mainstream economic concepts, including scarcity, opportunity cost, efficiency, cost benefit analysis, and how those concepts frame the choices faced by a society. It utilizes a simple mainstream economic model, the production possibilities curve (PPC), to capture some of these concepts and to display a variety of choices that a society might face. The chapter discusses these concepts and the PPC model to several economic issues, including an analysis of defense spending and its impact on economic growth. It draws on the work of political economists to show the limitations of these mainstream economic concepts and the PPC model in capturing economic reality. For Sony, the opportunity cost of running its computer division was the resources and staff that it could instead devote to the rapidly growing market for mobile devices. Political economists see the US military as supporting the dominant class of corporate leaders, wealthy owners, and politicians.