The Caves of Steel is the first "mixed genre" science fiction and mystery novel in Isaac Asimov's IRobot universe.
The novel's plot combines an 'unlikely cop buddy' story between Earth human Elijah Baily and Space robot R. Daneel Olivaw and solving the mystery of a murdered Spacer human: Roj Nemennah Sarton, a prominent sociologist.
The novel is a political allegory for McCarthy Era America. Earth is inhabited by billions of collectivists resistant to change and hostile to robots while the Spacers living on 50 sparsely populated extrasolar planets colonized by "individualists and materialists" who embrace social development that includes robots yet whose populations are too static to continue colonization of new worlds. The Spacers are also deeply fearful of microbial infection because of their weakened immune systems. Asimov's own liberal preference for a future liberal "middle way" between the extremes of individualistic capitalism and collectivist communism is expressed via forward thinking Spacer leader Dr. Fastolfe, who seeks human expansion combining growing human populations supported by robots. To achieve that goal, Fastolfe is willing to destabilize Earth society by introducing more robots.