This novel is another SF/detective story combination, taking Daneel and Baley to the planet Aurora, where a humaniform robot (one who looks like a human) - similar to Daneel - has been murdered. Only one man could have committed the murder - and he asks Baley to prove that he has not done it. This story, however, unlike the two previous books, is less orientated towards the detective style, and instead tries to concentrate on the political aspects of robots in general and the Spacers vs. Earthmen debate. It introduces Giskard, a robot, which despite not being humaniform, is at least as sophisticated in intelligence as Daneel. Both of these characters play a significant part in this book and the next.
'This long-awaited third in the series [of the Robot books] is as ingenious as always.'