This is the third full length Elijah Bailey SF mystery, set on the world of Aurora. Asimov has truly outdone himself in terms of world building (consistently top notch throughout his lengthy career) and characterisation, the latter of which was fairly week during his early years.He has captured extraordinarily well the Sir Arthur Conan Doyle-esque method of writing logical and rational deductive reasoning, explored fully throughout several lengthy interrogation segments. While sometimes teetering on the edge of tedious, these well fleshed-out chapters allow one to follow all of the incredibly interesting subtleties of Auroran life and culture, as well as the deductive power of the main character. I have yet to read any of Asimov's non-fiction, but if it is at all like any of the chapters mentioned above, it would have been written masterfully. Asimov would have been an extraordinarily talented communicator of science.The story line is interesting, but does take a back seat to the world in which Asimov has created. Aurora, the first settled and most powerful of the spacer worlds, has been gripped by a case of robotocide, where a highly advanced and irreplaceable humaniform robot has been disabled (effectively blue-screened). What follows is an intriguing look at the characters, customs and taboos that have run rampant on the utopian spacer superpower. As with the Naked Sun, Elijah's first off-world adventure, the planet of Aurora first presents itself as shockingly inviting. Large estates littered with greenery and animals are interspersed with robots, who fill the role usually inhabited by the working poor and underclass. Like the Naked Sun as well, the longer one explores this planet, the more broken and inhumane it seems, as many of the founding principles Aurorans have built up have been taken to their logical, but depressing, extreme.One criticism I do have however, is the almost ham-fisted insertion of psychohistory into the plot. If one has read the Foundation series, one would be aware that this theory is one of the largest themes throughout those books, and it is my opinion that it is completely unnecessary in the Robot universe, and has only been included to leave one more thread to join between the series. However, it is only a minor sub-plot, and is thankfully not explored fully.Regardless, a wonderful book. Not perfect, but the joy I had in reading this quality piece of SF makes up for it. 5 stars.