The old First Empire lies shattered. It has been swept from the Milky Way's bright spiral by the inexorable expanding forces of the First Foundation, established by the psychohistorian Hari Seldon - the only man to have foreseen the shifting patterns of the inhabited cosmos. But not even Seldon could have predicted the mutant menace of the Mule - a being of terrifying supernormal powers who, in his search for the Second Foundation, the mysterious hidden guardians of Seldon's plan, precipitats a savage struggle that lays waste whole star systems.