Almost all issues of public and private policy involve economics, as do our personal decisions. Is global warming the inevitable consequence of economic growth? Why are so many rich countries in debt? Does money bring happiness? Why do people migrate? Economics helps provide answers. To do so, it works closely with a wide range of other subjects including finance, business, politics, environmental sciences, mathematics and statistics. As well as standard topics of economic analysis, this interdisciplinary approach helps us explore a wide range of issues. There is little that an economist would regard as having no economic content.