Robert Silverberg's enduring classic about one man's journey to find salvation for a planet on the brink of destruction "Roum is a city built on seven hills. They say it was a capital of man in one of the earlier cycles. I knew nothing of that, for my guild was Watching, not Remembering."   For a thousand years, mankind has lived under the threat of invasion from an alien race. After the oceans rose and the continents were reshaped, people divided...