The murder mystery The Caves of Steel was Asimov's first big success as a novelist. In the book, the victim is a roboticist from Aurora, the first of 50 planets colonized by explorers from Earth (“Spacers”). The first colonists were selected for their abilities and so were healthier than average. Their ships were sterilized and so brought no diseases with them. The Spacers have become a sort of galactic upper class, more technologically advanced and military powerful than those left on the overpopulated, resource-strained Earth. While Earthlings live to about the same age we experience today, the Spacers expect much lengthier lifespans.
The contrast is highlighted by Elijah Baley, a police detective on Earth, and Hans Fastolfe, an Auroran politician who was a colleague of the murder victim. Fastolfe expects to live to be between 300 and 350. But he is wary of the drawbacks of such a long life. "If you were to die now," he says to Baley, "you would lose perhaps forty years of your life, probably less. If I were to die, I would lose a hundred fifty years, probably more." Fastolfe goes on to sketch out for Baley the mores of Auroran society. The birth rate is kept low, "Developing children are carefully screened for physical and mental defects before being allowed to mature," and humans constitute a sort of leisure class, with all the labor done by robots.