A solid sequel to "Caves of Steel," once again featuring Elijah Bailey cracking the case. What sticks out in this novel is its setting, the planet Solaria, where only 20,000 humans live in more or less total isolation from one another surrounded by hordes of robots to cater to their every need. Although not as brilliant as "Caves of Steel", the mystery is solid and the problems that Asimov reveals with Solarian culture are interesting.