Crucible of Time e-bog

Life had become too interesting on one world crawling across the rubble-strewn arm of a spiral galaxy. For as the system moved it swept up cosmic dust and debris. Ice ages and periods of tropical warmth followed one another very quickly. Meteors large and small fell constantly. Yesterday's fabled culture might be tomorrow's interesting hole in the ground. But society had always endured. Many thought it always would. Only the brightest scientists admitted that to survive, the race would have to abandon the planet. And to do that they'd have to invent spacecraft . . .This engrossing epic describes the development, over millennia, of a species from a culture of planet-bound medieval city-states to a sophisticated, technological civilization. With The Crucible of Time, John Brunner returns to the large-canvas science fiction he pioneered in his Hugo Award-winning, novel Stand on Zanzibar.First published in 1982.