Robots and Empire
Isaac Asimov's direct sequel to The Robots of Dawn, Robots and Empire bridges the Robot Trilogy with the chronologically later Empire and Foundation novels. 200 years after the death of the protagonist of the Robot Trilogy, Elijah "Lije" Baley, the balance of power has begun to shift back toward the humans of Earth, who have begun settling new worlds thanks to his efforts. The Spacers, descendants of the first wave of space colonists, are troubled by the apparent extinction of human life on Solaria, the latest- and most sparsely-settled of the Spacer worlds. Gladia "Solaria" Delmarre, Elijah's onetime lover and the only Solarian ever to emigrate, is sent along with one of Elijah's descendents, and her loyal robot servants R. Daneel Olivaw and R. Giskard Relentlov, to investigate. What they find there leads the real protagonists, Daneel and Giskard, to investigate a conspiracy with implications for human life on Earth and throughout the galaxy.
Because Elijah is only present posthumously and the story is not a murder mystery, Robots and Empire is not considered truly part of the Robot Trilogy, which therefore escapes Trilogy Creep... barely. Nonetheless, three of the four main characters debuted in that series (one in each book, coincidentally) and the setting is very much informed by the events of that series. Foundation and Earth, published a year after this book, would complete the link between the disparate elements of Asimov's major science fiction universe.
- Asexual Life Partners: Daneel and Giskard.
- Big Bad - Amadiro, as with The Robots of Dawn. He held a grudge.
- Bittersweet Ending - Giskard allows Mandamus to set the Nuclear Intensifier to its 150-year setting, in the hope that doing so will propel humanity to leave Earth once and for all, to settle a vibrant Galactic Empire. However, since he is not sure if he caused harm or good by that decision, his positronic brain begins to shut down. He uses his last moments to grant his psychic powers to Daneel and to reprogram Daneel to be fully compliant with the Zeroth Law of Robotics. See Fling a Light Into the Future.
- Borrowed Biometric Bypass - The threat is used.
- The Dragon - Levular Mandamus.
- Fling a Light Into the Future - Giskard casts Daneel, an all-but-immortal, psychic, Zeroth-Law-Compliant Ridiculously Human Robot, into the future as the sole guardian of humanity. 20,000 years later, in Foundation and Earth, he still stands as sentinel.
- Laser-Guided Amnesia
- Mind Over Manners - Or, rather, Mind over the Three Laws.
- Overclocking Attack - A device doing that to nuclear reactors is important to the plot.
- Science Marches On - Chernobyl was much, much worse than Three Mile Island; evolution does not apparently require radiation to proceed, but follows local conditions.
- Title Drop
- What Measure Is a Non-Human? - Solarian Overseers. Later, Amadiro tries to use it to argue that Earthmen aren't human... only to be told that Solaria sets a bad precedent.