James Blish's galaxy-spanning masterwork, originally published in four volumes, explores a future in which two crucial discoveries - antigravity devices which enable whole cities to be lifted from the Earth to become giant spaceships and longevity drugs which enable their inhabitants to live for thousands of years - lead to the establishment of a unique Galactic empire.
Read MoreAn outrageous imaginative coup...Crammed with high adventure yet illuminated by a searching intelligence, this four-part epic completely reinvented the traditions of space opera. - Paul J McAuley.Of the first importance. - The Encyclopedia of Science Fiction.This is the real heady wine of science fiction - exciting, intelligent, galaxy-spanning stuff. - Terry Pratchett.