Nearly all the action takes place on the planet Trantor. This planet is near the center of the Milky Way galaxy; it is as close to the black hole at the very center of the galaxy that a planet can be and still be habitable. Trantor is the center of the Galactic Empire, which has existed for thousands of years.

Over forty billion people live on Trantor, with the empire as a whole consisting of over twenty million worlds and trillions of people. Trantor is covered almost completely by interconnecting domes; few of its inhabitants ever venture outside. They are devoted largely to keeping Trantor and the Empire functioning. A huge bureaucracy is required to keep the vast government running, and the people of Trantor provide most of the bureaucrats.

Hari Seldon does most of his work at Streeling University, where he is supplied with offices by successive...