Economic activity is directed toward the satisfaction of human needs and desires. Some of the ways that have been developed for recording and analysing that activity are introduced in Chapter 5. One measure is national income, the limitations of which are discussed in Chapter 5. Increasing national income per head is what is known as economic growth, which is generally seen as a very good thing. Chapter 6 looks at what causes economic growth, and how it relates to the satisfaction of human needs and desires. Chapter 7 looks at economic growth in the light of economy–environment interdependence. The market is the dominant mode of organisation in modern economies, and Chapter 8 explains how market exchange can assist in satisfying human needs and desires, and provides some tools for studying the workings of markets. Finally, Chapter 9 is about markets in relation to the environment and sustainability. It establishes that markets themselves cannot be relied on to deliver sustainability.