Following his landmark story collection I, Robot, Isaac Asimov continued exploring the relationship of humans and robots in a series of intriguing and influential science fiction mystery novels starring detective Elijah Baley and his near-human partner R. Daneel Olivaw.

In this fourth and final mystery in the series, two centuries have passed since Elijah Baley's actions on Aurora sent settlers from Earth to new worlds all over the galaxy. The planet Solaria has been abandoned by humans, though countless robots remain. When settlers arrive to salvage them, something unthinkable happens—the robots attack. Accompanied by Gladia Delmarre and the robots Daneel and Giskard, a descendant of Elijah Baley sets out for Solaria to investigate—a quest that will lead them to a vast conspiracy and a revolution in the Three Laws of Robotics.