3Social establishments—institutions in the everyday sense of that term—are places such as rooms, suites of rooms, buildings, or plants in which activity of a particular kind regularly goes on. In sociology we do not have a very apt way of classifying them. Some establishments, like Grand Central Station, are open to anyone who is decently behaved; others, like the Union League Club of New York or the laboratories at Los Alamos, are felt to be somewhat snippy about who is let in. Some, like shops and post offices, have a few fixed members who provide a service and a continuous flow of members who receive it. Others, like homes and factories, involve a less changing set of participants. Some institutions provide the place for activities from which the individual is felt to draw his social status, however enjoyable or lax these pursuits may be; other institutions, in contrast, provide a place for associations felt to be elective and unserious, calling for a contribution of time left over from more serious demands. In this book another category of institutions is singled out and claimed as a natural and fruitful one because its members appear to have so much in common—so much, in fact, that to learn about one of these institutions we would be well advised to look at the others.