In the year 2020 A.D., not only the peace, but the continued existence of Earth as a habitable planet lay in the hands of two men: Carl C. Armitage, President of the United States, and Yu Lu-wai, Chairman of Red China. Neither were fools; both knew that the employment of the dreadful weapons that had been perfected in recent decades would result not in victory, but universal ruin. Yet both were being pushed toward the moment when they would strike — preventive war — which they would persuade themselves would annihilate only the other, before the enemy could strike back. But it was not only the peoples of Earth who trembled under the weight of impending doom. For the planet Jupiter was the home of a great race, humanoid in form — enough so that its inhabitants could disguise themselves as Earthmen — and the people of Omegricon had frequently sent intelligence expeditions to Earth, which they called Mugud or the Errant Planet. They knew how close to doom Earth was; and not only did they seek to avert events that would destroy a beautiful planet, but they hoped to cure the peoples of Earth of whatever madness it was that drove them toward war. For it was clear that not only one planet in the Solar System would be affected; the radiations of human nuclear weapons would reach far out into space and wreak havoc on Mars, Jupiter, and Saturn as well. The latest expedition, under the leadership of Zerdyl, had just returned from Mugud, and the news Zerdyl brought was grave indeed. War that would bring Earth's history to an end was very close. The Chinese Black Dragon satellites could annihilate the cities of the United States at any moment and an ultimatum had been sent to Chairman Yu. But the radioactive dust that the United States had perfected, very short-lived, could wipe out all life in vast areas within a brief period, and then be harmless but a few days later. And this was but one of the weapons the Pentagon had. There was but one course to take. Zerdyl and two companions must return to Earth to see if their superior talents could be effective in bringing about conciliation and disarmament before it was too late. If not, the war must not be permitted to start; the Ultimate Recourse must be employed in order to protect all life in the Solar System. The Ultimate Recourse! All the members of the High Council of Omegricon shuddered at that phrase, fervently hoping it would not have to be used. Here is a gripping novel of tomorrow by the author of “The Crimson Capsule” and “Lord of Tranerica.”