The Naked Sun by Isaac Asimov
This is the second of the robot mysteries, and in this one, Asimov explores one of the other worlds that are now in the galaxy. In the later Foundation novels, Solaria was the only one of the originally settled planets to still have human life on it, though it has evolved since this novel (in the negative direction one might have assumed from this one).
Baley is called to Solaria to help solve a crime - there is no such thing as crime on Solaria because there are only twenty thousand individuals on the entire planet, none of whom like to have any interaction with each other. Whenever they need to speak, they do so by viewing (basically holograms or very sophisticated webcams). They do not actually see anyone except for their spouses on a very occasional basis and then only to do their duties of adding to the population (which of course is prearranged).
Olivaw ends up being partnered with him again, partially because Aurora, the most powerful of the spacer planets, feels it would be helpful, and also because the other spacer planets are distrustful of Solaria and their way of life, having taken the idea of "individualism" to a new extreme (in comparison, life on Earth is compared to a beehive or compound where the needs of the many outweigh the needs of the few).
This novel was an improvement upon The Caves of Steel. Once again, it was amusing what people expected and didn't expect from the future - on Solaria, they are able to raise fetuses outside the womb in a laboratory but sex is still necessary to get the woman pregnant - it's just ironic that Asimov thought being able to develop embryos in a lab would be possible before artifical insemination and all that stuff (and I'm sure part of it was just set up for the novel). Of course, there are a few other things where clearly we have progressed beyond the novels - in the first novel, Asimov talks about community book and movie collections since it doesn't make sense for everyone to own their own since this is waste - however, in theory, we already don't need to have any of these things thanks to the internet and things like Kindle (obviously, I prefer my hard copies but it's just one thing were technology has already surpassed the novels - I don't think anyone could have imagined how complicated computers would end up being at this point).
I don't know why but the Foundation novels seem much more timeless to me while I feel like these sci-fi mysteries are already showing their age. Maybe it's because these focus so much on Earth while the original Foundation novels had no connection to Earth for the most part (there was one brief mention about archealogy and a origin planet), and seemed to take place in an entirely different galaxy, like Star Wars.