For two years, 1971 and 1972, I was on leave from Dartmouth College to serve as Director of the Department of Social Sciences of the United Nations Educational, Scientific and Cultural Organization (UNESCO). What I am about to say, therefore, comes from that experience, as well as a continuing concern over a longer number of years with the problems of international cooperation among social scientists. My principal aim is to explain how the UNESCO social science program seeks to respond to these problems in the period of social science development through which we are passing.