De revolutionibus orbium coelestium divided into six "books" (sections or parts), following closely the layout of Ptolemy's "Almagest" which it updated and replaced: Copernicus argued that the universe comprised eight spheres. The outermost consisted of motionless, fixed stars, with the Sun motionless at the center. The known planets revolved about the Sun, each in its own sphere, in the order: Mercury, Venus, Earth, Mars, Jupiter, Saturn. The Moon, however, revolved in its sphere around the Earth. What appeared to be the daily revolution of the Sun and fixed stars around the Earth was actually the Earth's daily rotation on its own axis. Copernicus adhered
The Sun Saboteurs Earth Quarter"; and in the UK under the original title in the omnibus "Two Novels". In the future, Earth has been devastated by war and disease and supports only a primitive agrarian society. Most Earthmen live elsewhere, as émigrés on planets that are populated by alien species. The author suggests that the human species is the only one plagued by "original sin", i.e. by an innate tendency to lie, cheat, kill; aliens have come to accept these traits without understanding them. The story takes place among a group of humans in the "Earth Quarter", a ghetto on the planet Palu