This is the third of Asimov's books featuring Elijah Baley and his robot partner Daneel Olivaw. The book is set on Aurora, the first of fifty worlds to be settled by Earth. These worlds, called Spacer Worlds, have distanced themselves from Earth and created a society that integrates robots and humans. Spacer society is more technologically advanced than Earth and Spacers continually threaten Earth's development.

In this context, a robot that looks like a human is killed, and Aurora's leading politician (and Earth's greatest supporter) is accused of the crime. Exactly why this is a crime (since the robot belonged to the politician) is never made clear. However, Baley is called to Aurora from Earth to work the case with Olivaw, also a human-looking robot. The situation is impossible and the clues are few and far between but Baley doggedly works the case, interviewing suspects and piecing things together. At the same time, he struggles with his feelings for Gladia, a beautiful Auroran woman he met on a previous case.

The solution to the mystery is less than satisfying and violates at least one of my rules for a fair mystery. Furthermore, I can't help but feel that neither Asimov nor his editor read the previous two books before publishing this one. There are several minor inconsistencies between this book and the earlier books that are distracting. For instance, in The Naked Sun, Daneel makes a big deal out of the fact that no Spacer, on any world, could identify him as a robot without close inspection. Yet in this book (set only two years later), Daneel and others emphasize the fact that any Spacer would know he was a robot from the most cursory glance. This is problematic since the reaction of Spacers to a humaniform robot plays an important role in both books. It should have (and could have) been handled differently.

Also, Asimov writes about sex for the first time in this book. He really shouldn't have. The sex scenes are cringe-worthy for their awkwardness, although they do in fact relate to the plot and have implications for the characters' relationships -- so it isn't gratuitous. It's just weird.

In this novel, Asimov is trying to connect the his robot, empire and foundation stories into one coherent piece (a project that continues in Robots and Empire, the next book in this series). I wish he hadn't done this. Tying these disparate elements together brings the back story to the foreground and shortchanges the mystery element of the book. Overall, this is a disappointing book, and doesn't live up to the previous two.

[note: this was a re-read for me]