John Middleton Murry Jr. Knihy

Earth, 2000 years after the final holocaust which drove man deep underground; a ghostly, deserted planet peopled only by the diligent robots who, century after century, silently harvest grain which no man will eat. Up into this eerie world comes Mel, a questioning young Roamer who has disobeyed the Law which says he must never venture into or beyond the Lost Levels. Together with three companions, and a companion not of this Earth, Mel takes on the awesome task of freeing human beings from the tyranny imposed on them by their remote ancestors; of justifying the agonized cry of Barney as he died in a Forbidden Level: "I am a man! Everything is for man!"

Earth is ravaged by tornadoes, and in their aftermath everyone becomes sterile. Certain people acquire psychic powers and can experience "trips" in each other's company, during which their consciousness appears to dislocate itself in time and space.