Sociology has become the science of the interview, and that in two senses. In the first sense the interview has become the favoured digging tool of a large army of sociologists. The several branches of social study are distinguished from one another perhaps more by their predilection for certain kinds of data and certain instruments for digging them up than by their logic. While the essential features of human society have probably varied within fairly narrow limits in all times and places where men lived, certain of these features can be more effectively observed in direct contact with living people. Others may perhaps be best seen through the eyes of men who left documents behind them. Sociologists have become mainly students of living people. Some to be sure do still study documents. Some observe people in situ; others experiment on them and look at them literally in vitro. But by and large the sociologist of North America, and in a slightly less degree in other countries, has become an interviewer. The interview is his tool; his works bear the marks of it.