Migrants in Europe was first published in 1969. In post-World War II years a move toward political and economic integration of Europe, exemplified in the formation of such organizations as the European Common Market and the European Free Trade Association, was initiated by high-level policy-makers. It was in no sense a popular movement with broad support. However, the European man in the street did gain economic benefits as a result of these arrangements and therefore did come to approve of them. But the political and social integration that goes along with economic integration calls for the international exchange of people and, ultimately, for a willingness on the part of national groups to allow all other national groups to participate in common elections or, alternatively, to grant political power to a supranational agency. Some interchange of people is now taking place, and the purpose of this study is to determine the extent of integration, suggest related problems, and draw generalizations to provide clues concerning the probable reaction to expanded forms of such integration in the future. The author stresses that without increased integration of people, the effectiveness of statesmen's agreements would be limited, and if large-scale rejection of such integration develops, progress toward European unity will be nullified.