The Caves of Steel by Isaac Asimov
'The Caves of Steel' is the story of the unusual partnership between a New York plain clothes cop (Lije Baley) and a humanoid robot (R. Daneel Olivaw), or 'positronic cop'. Asimov's portrayal of futuristic human life is one of self-imposed imprisonment by humans within the caves of their highly structured super-cities. The backdrop of the story is that of a xenophobic city culture wherein the citizenry has abandoned all semblance of rural and suburban life for the efficiency of the city. Asimov broaches Malthusian theory to introduce the idea that past human generations have opted out of the crowded uncertainty of earth life to venture to other planets. The earth emigrants are referred to as 'spacers'. The spacers return to earth in an effort to inform them of a better life out in the cosmos, but they are dismissed by the majority of the city-dwellers (Earthmen) as arrogant foreigners. Spaceport is a city established to house the spacers. Spacers do not venture out of Spaceport because ever since their exit from earth they no longer have the necessary antibodies to ward off earth diseases. The story starts with the death of a prominent spacer within the city of Spaceport. Baley is charged with the case by his commissioner, with one catch- he has to take on a robot partner. Given Earthmen's distrust and hatred of robots, this makes for an interesting sub-plot. The story unfolds neatly, and maintains a steady pace. While the background is futuristic sci-fi, it settles nicely into the realm of mystery novel.