The Naked Sun
Isaac Asimov
 Ultimately, we find out that Delmarre's neighbor and fellow roboticist Jothan Leebig was working on a way of subverting the robots' inability to kill humans. This was achieved by understanding a missing word in the Three Laws of Robotics: "knowingly". He used this knowledge to cause the death of Rikaine at the hands of his wife Gladia, because Rikaine was opposed to his plans. Later on, he also managed to poison the Security Secretary using a pair of robots. The key to this technique is that a robot cannot knowingly kill a human or knowingly allow a human to come to harm. But if the robot does not know that its actions will cause harm, then it will not be stopped by the Laws. The future implication of this was pointed out by Elijah, that it can be extended to the point at which robots could be used to fight wars. (In the Asimov universe, this would otherwise be unthinkable, given the Three Laws.) Leebig kills himself before he can be taken into custody, because of a very Solarian fear of human contact. The irony is that the "human" he was afraid of was Olivaw, a robot. Despite knowledge of Gladia's guilt, Baley never discloses her role in the murder—in part because he feels sorry for her and believes that her breakdown was caused by the pressure of the Solarian way of life. He manages to have her sent to the Spacer capital planet of Aurora, where she can further her growth as a human being, something she could never do on Solaria. After investigating the murder to a satisfactory conclusion, Baley returns to Earth a hero. The information he brings back is invaluable to the government, which was predicting the downfall of Spacer societies; the similarities between the nature of Solarian society and Earth society in their closed natures suggests a fundamental flaw in the Terran society. A more thorough description of the aftereffects can be found in the sequel to the Naked Sun, The Robots of Dawn. We also discover the remote end-point of Solaria's odd development in Foundation and Earth. The Foundation series and the Spacer/Robot series seem originally to have been separate, though with some overlap of ideas. If the Galactic Empire is the far future, where have the robots gone? In Foundation's Edge Asimov begins to supply the answer, expanded in the other sequels and prequels.