Robots and Empire

Last instalment in Asimov's robots series is the first where a human being is not the main character. Elijah died decades and decades ago, Fastolfe is dead too; Earthmen have settled many planets and these new spacers are called "Settlers". But the peace imposed by Fastolfe is now coming to an end and tension is growing between Spacers and Settlers.
R. Daneel Olivaw and R. Giskard Reventlov are now property of Gladia who received them from Fastolfe. The last time they saw, on a spaceship some 5 years after The Robots of Dawn, Baley made Gladia promise to always trust Giskard... She had never understood why but is now reminded of this promise!
On Aurora, Amadiro is brewing his long due revenge against Fastolfe and Earth, and young Levular Mandamus presents him a plan to destroy Earth. Meanwhile, on Solaria, inhabitants have disappeared, and robots kill humans!
Daneel and Giskard will embark on a journey with Gladia and D.G. Baley (a descendant of Elijah, named after them) and will try to find a solution to their problems: can they find a way to work outside the context of the 3 laws and thus doing, can they save humanity?

SPOILER ALERT: In the end, they will come up with the superseding zeroth law (a robot may not injure humanity or, through inaction, allow humanity to come to harm), will get the first ideas of psychohistory (as dealing with large populations of human beings) but will not prevent Earth to be slowly rendered radioactive; after having thus ensured that humanity will survive and expand, Giskard succumbs. His last act will be to modify Daneel to give him his abilities of mind reading and adjusting...

At least!!! Now I know the whole story of why is Earth radioactive! This book was a great read as usual and it is fun to see the 2 robots trying to emulate the thinking of Elijah.

Since I've now finished the robots cycle, I guess I'll go back to Zola :)