|Robots and Empire|
Asimov is really drawing the threads together in this novel. He is taking his immensely popular Robots series and tying it to his immensely popular Foundation series. For my money, he pulls it off, if not precisely gracefully, but then Asimov's writing is not best described as graceful. (And it's not described as klunky, either... just simple and to the point.)
Two centuries after the events of Robots of Dawn, the planet Solaria has been abruptly abandoned, or so it seems. Settlers— people of Earth who have moved to space— have lost several ships in attempting to determine exactly what has happened, and they've come to the one woman who can help, the Solarian woman who left the planet for Aurora.
But that's not what the story is about. The story is about Daneel Olivaw and Giskard, another robot with some surprising talents, and their attempts to go beyond their limitations in order to do what is right. Daneel in particular, because he has been made to mimic humanity so closely, tries to bring morality to the table in a means of superceding the First Law, "No robot shall harm, or allow to come to harm, a human being." This is actually dangerous as straying too close to the limits of their programming might cause them to permanently shut down, but they feel the threat is important enough to risk it.
Oh, the threat? Simply a very smart man with a long-standing grudge against Elijah Baley— and, by extension, all the people of Earth. And in his associate, a man who has the means to do great damage to Earth... even though he wants to spread it out over time, so as to not harm too many.
And because the robots cannot harm them, they cannot stop them... or so they think.
But c'mon, it's Asimov, so you know the good guys will win (as long as it's Robots or Foundation. I give no guarantees in regards to Nightfall.)