Yet Einstein, working away in majestic solitude, has been trying all these years to construct a vast intellectual edifice that would embrace all the laws of the cosmos known so far, including the quantum, in one fundamental concept, which he designates as a “unified field theory.” Early in 1950 he published the results of his arduous labors since 1915. This he regards as the crowning achievement of his life’s work, a unified theory that bridges the vast gulf that had existed between relativity and quantum, between the infinite universe of the stars and galaxies and the equally infinite universe within the nucleus of the atom. If he is right, and he has always been right before, his latest contribution will prove to be a greater synthetic achievement of the human intellect than ever before, embracing space and time, matter and energy, gravitation and electromagnetism, as well as the nuclear forces within the atom, in one all-encompassing concept. In due time this concept should lead to new revelations of nature’s mysteries, and to triumphs even greater than those which followed as a direct consequence of all earlier intellectual syntheses. If the synthesis of matter and energy led to the atomic age, what may we expect of the latest, all-inclusive synthesis? When Einstein was asked about it he replied: “Come back in twenty years!” which happens to coincide with the end of the hundred-year period recorded by the brothers Goncourt: God swinging a bunch of keys, and saying to humanity: “Closing time, gentlemen!” The search for new intellectual syntheses goes on, and no doubt new relationships between the diverse phenomena of nature will be found, regardless of whether Einstein’s latest theory stands or falls in the light of further discovery. Physicists, for example, are speculating about a fundamental relationship between time and the electronic charge, one of the most basic units of nature, and there are those who believe that this relationship will turn out to be much more fundamental than that between matter and energy. Should this be found to be true, then the discovery of the relationship between time and charge may lead to finding a way for starting a self-multiplying positron-electron chain reaction, just as the relationship between matter and energy led inevitably to the self-multiplying chain reaction with neutrons. If this comes about, then closing time will come much closer. Yet the sound of the swinging keys need not necessarily mean closing time for man at the twilight of his day on this planet. It could also mean the opening of gates at a new dawn, to a new earth—and a new heaven. APPENDIX THE HYDROGEN BOMB AND INTERNATIONAL CONTROL