After discussing the general beliefs in and attitudes towards immortality and the peculiarities manifested in the conception of immortality, the author raises the questions: 'What are the instinctual forces which enter into play as soon as the problem of life and death is faced and finally solved in favour of immortality?' and 'Which topological units of the human personality play the decisive rôle in the solution of the problem?' He answers by an analysis of examples of behaviour in the presence of death, in which the interaction of ego and super-ego are evident. He concludes that the primitive ideal of immortality has evolved in the course of thoussands of years into a sense of immortality, and this sense, acting as if it were a powerful independent impulse, plays a major rôle in the elaboration of our theories of social salvation and in the altruistic aspects of our communal life. In neuroses and psychoses the influence of the sense of immortality is indirect, making a kind of short circuit between its infantile residues and the impulses which it generates in our purely social adaptation.