A World Apart by Sam Merwin Jr., Science Fiction, Fantasy 12+

📕 Yet there is always the possibility that somewhere, somehow, somewhen, it has already been put to use. A possibility which Sammy Merwin here considers in highly intriguing and human terms. Let's go back with Coulter. . . . Most men of middle age would welcome a chance to live their lives a second time. But Coulter did not.He thought of Jurgen, of Faust -- for in some miraculous way he had reclaimed his youth or been reclaimed by it. The face that looked back at him was fresh-skinned, unlined, unweathered by life. He saw with surprise, from the detachment of almost two decades, that he had been better looking than he remembered.