=The Subject-Matter of Economics.=—The study of economics does not concern itself with all the possible wants and aspirations of men. It deals only with the production, distribution, and consumption of those things which satisfy man’s desire for (_a_) material objects and (_b_) personal services. In other words economics is a subject which concerns itself with the production, distribution, and consumption of _economic goods_, a term which includes material possessions known as wealth and also such personal services as have an economic value. Not all things of a material sort are economic goods; air and sunlight, for example, being free to all, require no effort on the part of man to obtain. They are called free goods. We apply the term economic goods only to such things and services as satisfy human wants and are not to be had free. Requiring effort to produce, these economic goods are limited in supply and hence have a value in exchange for other goods. For this reason they are commonly spoken of as _wealth_. Certain personal services, those of the physician, the lawyer, the foreman, the laborer, also have an economic value in that they are limited in supply, satisfy material wants, and can be exchanged for tangible goods. These services form a part of the economic activities of society, a very important part. So the study of economics includes these personal services as well. [Sidenote: Present and future economic goods.] =The Consumption of Wealth.=—All economic goods are produced for the purpose of being used. This use is what the economist calls _consumption_. Some economic goods are in finished form, ready for immediate consumption at any time; others are in the form of raw materials or half-finished products not yet ready to be used. Hence we distinguish between present and future economic goods. Economic organization strives to manage matters so that a sufficient supply of economic goods will reach their finished form in time to fill the demands that arise. This demand on the part of the consumers determines the methods and amount of production. If there is no demand for a particular kind of economic goods, these goods will not be intentionally produced. On the other hand a vigorous demand will encourage production and speed up the process of distribution. [Sidenote: Demand and supply.]