No exact answer can be given to that question. One man’s play is another man’s labor,—gardening, fishing, acting on the stage, for example. But economists usually define labor as “human exertion or effort directed toward the creation of economic goods”. This includes mental as well as physical exertion. All who are engaged in the production of material things or personal services for the satisfaction of human wants are engaged in productive labor. [Sidenote: The economic importance of labor.] Labor, of course, is of great economic importance. The natural resources of the American continent were as great three hundred years ago as they are today; yet they were practically useless in satisfying human wants because the red man would not and could not bestow his labor upon them. It remained for the white man to transform natural resources into economic goods. This he has done not only by the use of muscular exertion but by the application of intelligence. Labor is never an end in itself; it is always a means to an end, and this end is the satisfaction of human demands. [Sidenote: The simple and complex forms of division of labor.] =Division of Labor.=—In applying their labor to natural resources men soon found that the best results could be obtained by apportioning different tasks to different workers. This is called the _division of labor_ and it has been one of the great factors in the progress of production. In its simpler form, division of labor merely meant that each workman confined himself to a simple occupation and carried through all the processes of production in that particular trade. The cloth-maker, the shoemaker, the implement-maker performed all the work of making cloth, shoes, or implements from start to finish. This simple division of labor was practiced in very early times. But as the world moved forward a more complex division of labor developed and this is particularly a feature of modern production. In this development the individual worker is assigned to make only a part of a commodity. The making of cloth is no longer a trade, but embodies a series of trades—that of the wool-carder, the spinner, the weaver, the fuller, the dyer, and the finisher. In the modern shoe factory one employee cuts the sole, another trims it, a third turns the heels, a fourth sews the uppers to the sole, and so on. There are more than twenty distinct operations in the making of a factory shoe, each requiring special skill on the part of the worker.