A LARGE proportion of the people in our society live together in families, who carry on a life which, though constrained within limits set by the mores and by law, reflects the peculiarities of their members and the contigencies to which their times and surroundings subject them. Likewise, people go to work in -factories; they study, teach, and play in schools, ,or at least, as citizens, are taxed for their upkeep. If they are residents of Latin-American villages, they will engage once a year in a great fiesta; if they live in the rural Middle West, they might possibly be annually mobilized by a county fair. In all these instances people are mobilized to take their places-important or minor, casual or regular, voluntary or involuntary-in a collective enterprise carried on in a somewhat established and expected way. The things I have namedand many others as well-have been called institutions. Some of the other things which have been called by the same name are of quite different orders. It is not my purpose to explore the limits of a concept. I rest the case by saying that I conceive the study of institutions to be part of the study of society in action. The center of the field lies where the action takes place within forms which are somewhat firmly established. The student of institutions will, however, be interested also in seeing how social forms become established, how they bend and yield under pressure, how they give place to new, and what functions they perform. lie will, if his interest is in the structure and functioning of society, be only incidentally concerned to answer categorically the question whether the newspaper, the beer parlor, the Republican Party or property is an institution at a given moment. It is obvious that many people other than sociologists have been and are interested in institutions. That being so, what is the place of sociology in their study? Sociology is that one of the social sciences which is especially and peculiarly, by intent and not by accident, a science of social institutions. In our branch of social science there have been developed concepts for analysis of social control and collective behavior. Following Sumner, we have been particularly aware of the nonlogical aspects of social behavior; following Cooley, as well as Sumner, we have taken account of the distinction between the informal pressures of primary group life and of the unthinking following of custom, on the one hand, and the formal and rationalized procedures of institutions, on the other. Sociologists have developed a frame of reference for describing the processes by which social movements arise and by which, under certain circumstances, they leave a residue of new forms of expected and routine action in the structure of a society. Our equipment includes-or should do so-the rich body of concepts developed by Max Weber for description of the ways in which the prophet becomes the priest, the political sect becomes the legitimate and highly structured mechanism of the state, disciples become a bureaucracy, and for similar processes by which the unusual, the illegitimate, and the romantic forms of collective behavior or even rational business enterprises become imbedded in society as legitimate and traditional routine. These concepts are part and parcel of sociological discourse. In no other field has an adequate parallel set of concepts been developed. It does not follow that sociologists-by whom I mean people who use these concepts and are interested in these processes-know more about social institutions than other social scientists. In fact, sociological investigation has been gencrally limited to a few institutions. The most extensive work is that relating to the family. Meanwhile certain institutions have become the peculiar interest of students in other fields. Incidentally, one of the besetting sins of us sociologists has become what unkind critics call sociologizing about institutions we have not particularly studied. This brings us to consideration of the investigation of social institutions by the other branches of social science. Each branch, in so far as it has scientific pretentions, has its own frame of reference for discovering facts, a sort of lens which hauls certain problems and facts into focus. Each of them has also a conventional content, arising partly from the practical problems with whose solution *Read before the Mid-West Sociological Society, April 1941.