One of the great difficulties with which sincere social workers have to contend in almost every field of their efforts is that practical economics has advanced so much more rapidly than practical sociology. Our knowledge of the technique of production and transportation, and of the industrial arts, has made phenomenal strides in the past century. The growth of cities, the development of the factory system, easy means of communication between all countries, the growth of the world market, advances in agricultural methods which have made the soil much more productive per unit of labor, have coöperated to introduce a new set of social conditions and problems with which we have not yet learned to grapple. Our knowledge of how to produce satisfactory social relations is far behind our knowledge of how to produce wealth. This is strikingly evident in the matter of immigration. If transportation conditions and means of communication had remained as they were at the time of the Revolution, our present immigration situation could never have arisen. There would have been a natural barrier which would have prevented too large increments of European population from entering the new country while it was working out its problems and gradually finding itself. The problems of immigration which presented themselves would have been of sufficiently moderate dimensions so that they could have been dealt with as they arose. As it is, the recent rapid development of communication has made the ease of immigration so great that we have been overwhelmed by the resulting problems. The movement of millions of people from one region to another is a phenomenon of prodigious sociological import. Modern mechanical progress has made this movement possible, before the nations or the individuals concerned have advanced far enough in social science to know how to make the most of it.