Die Atombombe und die Zukunft des Menschen (R. Piper, München) is the topical title of Karl Jaspers's latest book. His intention is excellent, he wants to arouse the conscience of man in face of the deadly danger of atomic warfare. It would be most interesting to compare this book of more than 500 pages with Bertrand Russell's corresponding short publications which concentrate on practical proposals. In order to do justice to Jaspers the English reader should, however, keep in mind that the author had to overcome formidable obstacles. His subtitle, Politisches Bewusstsein in unserer Zeit, indicates that he does not only wish to discuss the present dangerous situation and the means for mastering it, but also to lay the foundation of a Political Philosophy. But here he is faced with two brute facts. First, the Germans are almost by nature un political and falsify by their existence a famous Aristotelian dictum. Their political sense or instinct is, for complex psychological and historical reasons, underdeveloped; a fact which is, paradoxically, of great political importance. Secondly, a German Political Philosophy in the Anglo-American sense does not exist; it forms part of the Rechts-und Staatsphilosopie (cf. Hegel's Philosophie des Rechts, which should not be translated as Philosophy of Right) or of sociological studies. Consequently, Jaspers has to construct his Political Philosophy on the basis of his own Philosophy of Existence, an interesting experiment, beset with formidable difficulties. Here again he remains the gliding philosopher (der schwebende Philosoph), whose analysis of our political predicament moves in “possible perspectives” so that in the end everything remains in suspense (Es bleibt alles in der Schwebe). Indeed, Jaspers holds that rationally atomic warfare cannot be eliminated and that the total destruction of mankind is probable. He therefore appeals to every human being for a radical change of heart which alone could avert the disaster. This change of the “essence of man” remains a Utopian hope. Nevertheless, Jaspers is right in appealing to everybody's conscience. He confirms, moreover, that his existentialism cannot provide the basis for a Political Philosophy.