I am re-reading all of Asimov's novels, and I am surprised to find myself rating this book higher than the Foundation series. In fact right now I believe it is Asimov's best novel. Generally I am not that interested in robots, but in this case I was enthralled with Asimov's brilliant characterizations of Daneel and Giscard as evolving beings. The two robots, one of them humaniform and the other telepathic, engage in philosophical discussions about what the First Law (not harming a human being) really means. Their definition of "harm" gradually expands to include the general well-being of humanity. As they follow this logic to its conclusion, they transcend their own programming, to the point where they have evolved from mechanical slaves to near-gods. In fact these robots are nobler than most human beings, as they have no selfish or base motives at all.

I was also fascinated with Asimov's nuanced portrayal of Gladia, the Solarian woman who first appeared in The Naked Sun. In that novel she started off as a self-absorbed aristocrat, like all Solarians. By the time she appears in this novel, (several hundred years later) she has evolved beyond the Spacers' prejudices and found the strength to become a public spokeswoman for peace between Spacers and Settlers.

As another reviewer said, I was not happy with the idea that Earth had to be destroyed in the interests of creating a galactic Empire. I definitely don't believe that Earth is unique as an abode of intelligent life, and that the universe is full of empty planets just waiting for humans to move in. As we are finding new planets around other suns, it is quite improbable that humans are alone in the universe. However, I will ignore these reservations and accept Asimov's writing on his own terms.

At the end of this book I was really wishing for another novel, which would show what finally happened between the Spacers and Settlers.

This is the sequel to "The Robots of Dawn" (which happens to be my favorite Asimov Robot novel.) As such, it is must reading for anyone who is a fan of Asimov's Robot and Empire series, as this story unites the two, explains how Planet Earth became a backwater, and explains how unlimited human colonization of the Galaxy begins.

Elijah Bayley is dead, but Robots Giskard and Daneel are carrying on his work, sort of. More would be telling, but this is an interesting story, although not nearly as engaging as "The Robots of Dawn" in my opinion. The novel also has some tiresome anachronisms dealing with nuclear power that already dates it.

This one moves a bit too slowly to fully engage the reader, and it drags at times. Also, in this story Daneel and Giskard start to act in a fashion that I just don't accept. These are machines, and I am not sure that I am persuaded that they can reprogram themselves to act in the manner that this story suggests. Well, the great Asimov created these characters, so I suppose ultimately it was for him to say, but that is my own opinion, as a long-time die-hard Asimov fan.

Overall, all Asimov fans will enjoy this novel, even if it is not, perhaps, Asimov's best.

VoodooLord7 provides an extremely enlightened review of the book, especially in his explanation of where the book fits within the works of Asimov. However, I would like to give an alternate view of the book, as far as a stand alone creation is concerned. Far from being "not great in and of itself", it is perhaps one of Asimov's greatest book concerning the evolution of robots and the emergence of artificial sentience. While the first three books had been about the relationship between the protagonist Elijah Baley and the robot Daneel and later Giskard, here the book describes the very real friendship between the two robots themselves. It outlines the process by which these two philosophising robots attain emotions and how only in unison were they able to urge the other to break the bonds of their intrinsic programming. In the end, they choose to serve humanity, rather than any individual masters. This book does much to support the liberalisation of robots better than any of Asimov's other books, as it approaches the subject using a series of intelligent discourse, as opposed to taking the populist Pinocchio argument, such as the one used in the more popular "The Positronic Man" (i.e. Bicentennial Man film) and mass media like "A.I." and "Star Trek". In "Robots and Empire", the robots have no desire to become humans - that would a downgrade of their abilities. Instead, they are in search of a new branch of science that would formulate the laws that govern human thoughts and behaviour, and in doing so, would permit them to act as guardians and guide humanity along the path of peace and prosperity.

In some ways, this novel, which clearly and explicitly links three of Isaac Asimov's series--Robot, Foundation, and Empire--is the development of a new law of robotics. Of course, all fans of Asimov know the three laws:

1. A robot may not injure a human being or, through inaction, allow a human being to come to harm;
2. A robot must obey orders given it by humans except where such orders would violate the First Law;
3. A robot must protect its existence unless such behavior would violate the first and second laws.

This novel introduces a critical new law, what R. Daneel Olivaw (the classic Asimov robot) referred to as the "Zeroth Law." This law reads:

"A robot may not harm humanity, or by inaction, allow humanity to come to harm."

And this introduces a tension into the first three laws. This novel shows the implementation of this new law, by Daneel's friend (a telepathic robot), R. Giskard Reventlov.

In some senses, the actual plot of this work is not so central. It is indifferent, in fact, as a mystery, compared with the first three Robot novels (as well as short stories). Elijah Baley, who had worked with Daneel in earlier mysteries, has been dead for a couple centuries; Daneel is now on his own (with Giskard). But it represents an effort by Asimov to begin to link his three mighty series: Robot, Empire, and Foundation. The Zeroth Law is what begins to link these, with Daneel as the key player. One would have to read later novels in the Empire and Foundation series to understand the profound consequences of the Zeroth Law in his hands.

Anyhow, this is not a very good mystery on its own, but it is an important work beginning to link the three series, answer questions that had heretofore not been answered.

This is my favorite out of the Robot series by Asimov. This book is NOT a mystery like the others. It is more of a tie in to the Galactic and Foundation series. I feel that this book gives more "personality" to a one Daneel Olivaw. A must have for Asimov fans and a should read for sci-fi lovers.