The city is winched along tracks through a devastated land, full of hostile tribes, in Christopher Priest's mind-bending science fiction masterwork, winner of the 1974 British Science Fiction Association (BSFA) Award and a finalist for the 1975 Hugo Award. Rails must be laid ahead of the city and removed in its wake, but if the city does not move, it will fall behind the "optimum" into a crushing gravitational field. The alternative to progress is death. The rulers of the city make sure that its inhabitants know nothing of this. But the people are growing restive, the population is dwindling, and the rulers know that the city is falling further and further behind.