Foundation and Empire

Libro Usado, Tapa Blanda. Led by its founding father, the psychohistorian Hari Seldon, and utilizing science and technology, the Foundation survived the greed and barbarism of its neighboring warrior-planets. Now cleverness and courage may not be enough. For the Empire—the mightiest force in the Galaxy—is even more dangerous in its death throes. Even worse, a mysterious entity called the Mule has appeared with powers beyond anything humanly conceivable. Who—or what—is the Mule? And how is humanity to defend itself against this invulnerable avatar of annihilation?