Imagine a time when Earth is so heavily populated that Cities are domed over, so that most of humanity never sees the sun or feels the wind. This is the Earth of The Caves of Steel.

There has been some colonization of space; however, the Spacer colonies are hostile and feel immensely superior to the men of Earth. But when a prominent Spacer is murdered in Spacetown on Earth, they request an Earth detective try to solve the case, with a humanoid robot assistant.

Earthmen do not trust robots on Earth, as they are taking over many jobs, causing people to lose all status and be sent to a subsitence living. Elijah Bailey, the detective, dislikes his partner immensely at first, despite his complete resemblence to a human, for that reason.

This is a great murder mystery story blended into science fiction. Daneel Olivaw, the robot, is a great character in his own right, and appears in many more of Asimov's stories in this universe, beyond the Robot series.

The science won't impress much these days, aside, perhaps, from the ability to create the Cities and feed everyone almost exclusively on foods created from yeast, but as this story is more than 50 years old, some things do have to be forgiven. The extrapolation on how to make life more efficient, to make the Cities possible, is both uncomfortable and realistic. Little efficiencies like dining halls for most or all meals rather than kitchens in every home, make sense, even if I wouldn't want to deal with it.