If I had a nickel for every scifi novel I've read about a civilization of intelligent arachnids, I'd have 10 cents. Which isn't a lot, but it's weird that it's happened twice (the other book is Vinge's A Deepness in the Sky).

In a classic far-future, arrogant scientist Avrala Kern is about to complete the final steps of an ambitious project to uplift monkeys on a newly terraformed planet orbiting a distant star. Her experiment is sabotaged at the last second by an anti-promethean extremist, one tentacle of a war which devastates human society. There are three groups of survivors.  Kern, or a hybrid of Kern and an AI upload, slowly decaying in the observation pod around the planet. A few people back on Earth, who somehow made it through the civilization shattering war. And newly uplifted spiders on Kern's world.

The more interesting plotline follows the spiders.  Mammals on Kern's world other than monkeys were rendered immune to the uplift virus, but insects and arachnids were overlooked. Portia labiata, a species of jumping spiders, becomes larger, smarter, and more empathetic. Over repeated generations, key Portias, represented by the names Portia, Bianca, Viola, and Fabian, experience rapid technological and social evolution. The spiders are natural biotechnologists who domesticate other insect species to do their brute labor, especially ants, who are also uplifted into non-sentient Turing automata. The spiders make contact with an increasing insane Kern via radio, and work towards the scientific method and social equality, with females being the dominate sex. The spiders are always delightful.

Less delightful are the human survivors of the cold sleep ship Gilgamesh, represented by the classicist Holsten. Classicists are specialists in understanding the technology and culture of the Old Empire, Kern's culture.  Old Empire technology is both immensely more advanced than anything contemporary humans possess, and also frequently fatal.  The lingering side-effects on the biosphere are rendering Earth uninhabitable. The survivors barely have enough technology to launch sleeper ships to nearby stars, but a primitive sleeper ship is a bad lifeboat.  The  Gilgamesh is turned away from the spider's world by Kern, the crew suffer their own splits and mutinies and usual insanity, becoming an impromptu generation ship with slowly aging cold-sleep leaders.  This is a story we've seen before, and done with slightly above average style. Compared to the very alien yet coherent society of the spiders, there's no sense that the humans are much different from say, a 21st century sleeper-ship. It's a missed opportunity, given how much has happened in the interim, at least to gesture at.

The final confrontation, between human and spider, is not to be missed, and is an optimistic take on the better angels of our nature, even if they may have spinnerets rather than wings. (The many eyes and 'Be Not Afraid' are still true.)