For centuries genuine social thinking was confined largely to a few of the intellectually élite. These few lived, and did even their social thinking, in a more or less isolated way. It was not until the first decades of the last centuries that social thought began to be scientific in character, that is, became sociological. Sociological thinking, however, was isolated and uncorrelated for many years. In the last decade of the nineteenth century, sociology began to develop a considerable body of thinkers and to create a new morale. There were many disagreements that tended to break the new science asunder. The opening decades, however, of the twentieth century witnessed a development of sociological thought that was followed by the establishment of the teaching of sociology as a profession. With the rise of professional sociologists, the dissemination of socialized thought became noteworthy. For a long time sociology was considered only as a post-graduate study. In the last few years, however, sociology has been making its way downward in college and university curricula, until it is being widely taught to college freshmen and sophomores. In this connection there is a variety of textbooks that have been written to meet the needs of beginning students. There are some teachers who would introduce sociology through anthropological studies, beginning with the origin of man. Others would give a survey or prospectus of social institutions, processes, and problems.[XXVIII-1] Still others would deal only with social problems. Then there are those persons who would build a text-book around a central theme, tracing it through social relationships. For advanced work in sociological thought there is a variety of treatises dealing with systems at once profound, complex, and fundamental. For high schools, the technique of sociological teaching is in the beginning stages. The importance in high schools of social science teaching is generally recognized, but there has been great difficulty in effecting an agreement among the various social science branches. Some high school teachers prefer a “social problems” course, although the demand is growing for a “social science” course, extending throughout the year, dividing the time more or less evenly between economics, sociology, and civics. There are other high school teachers who contend that sociology can be taught best in a general “citizenship” course. One of the specific difficulties is that the high school curriculum is full, and that the representatives of none of the established courses are willing to see the subjects in which they are interested crowded out. Another difficulty is the power which the self-culture and self-development concepts possess. The equal importance of the social culture and social development concepts is being recognized, but with amazing slowness.