'Probably at no other time in the history of man's struggle for survival has the threat of extinction been such a real one.' The rôle of the social scientist in relation to this grim fact is examined in detail, with particular reference to what constitutes social tension. Modern social psychologists no longer recognize the dichotomy of individual and group psychology. Society desperately needs to study the problems of leadership. More data must also be obtained on the way in which social forces determine the structure of personality. Whether or not social science will be allowed to find the answers to fundamental social problems lies in the hands of those 'who now hold the actual economic, political, and military power to decide man's destiny in the immediate present—a decision that will determine whether or not he will be permitted to have a future'.