Esta excelente novela de ciencia ficción de Isaac Asimov, maestro del género, es el segundo libro de la «Serie de los robots», primer bloque de su famosa «Saga de la Fundación». En el Enclave Espacial, a las afueras de la Ciudad de Nueva York, un científico de los Mundos Exteriores ha aparecido asesinado. El detective Elijah Baley tiene que ocuparse de este caso en la para él inquietante y odiosa compañía de un robot humanoide: R. Daneel Olivaw. La investigación es delicada ya que puede terminar con el equilibrio entre los descendientes de la colonización estelar, en perfecta comunión con sus robots, y los habitantes de la Tierra, que, refugiados en grandes metrópolis subterráneas a las que llaman Ciudades, sobreviven precariamente a la falta de recursos naturales y temen a los robots.ENGLISH DESCRIPTIONA millennium into the future, two advancements have altered the course of human history:  the colonization of the Galaxy and the creation of the positronic brain.  On the beautiful Outer World planet of Solaria, a handful of human colonists lead a hermit-like existence, their every need attended to by their faithful robot servants. To this strange and provocative planet comes Detective Elijah Baley, sent from the streets of New York with his positronic partner, the robot R. Daneel Olivaw, to solve an incredible murder that has rocked Solaria to its foundations.  The victim had been so reclusive that he appeared to his associates only through holographic projection.  Yet someone had gotten close enough to bludgeon him to death while robots looked on.  Now Baley and Olivaw are faced with two clear impossibilities:  Either the Solarian was killed by one of his robots--unthinkable under the laws of Robotics--or he was killed by the woman who loved him so much that she never came into his presence!