Readable! A sci-fi/fantasy hybrid novel with plenty of world-building, using the standard narrative technique of alternating two story threads that unify at the finale.
An Earth ship deposits an "uplift nanovirus" on a planet, accelerating evolution there, and this inadvertently causes a species of spiders to develop a sophisticated civilization. That's one of the story threads. The other thread follows a group of humans on a multigenerational sleep-ship, seeking a new home after fleeing an uninhabitable, post-collapse Earth.
One warning. Do not read this book if you are grossed out by spiders. Or do! There's a well-executed mild horror movie vibe throughout.
The story gets you thinking about the stages of development of cognition and the implications of sentience (a coincidental tie-in to Julian Jaynes' wonderful book The Bicameral Mind). As the spiders evolve into the dominant species on their planet, they learn a sort of agriculture and animal husbandry, they "employ" (enslave really) various ant species on their planet as Helots, they develop religion with orthodoxies and heresies, they even have a sort of men's rights movement as male spiders fight for equality under a female-dominated species. The author is quite creative with his ideas and it rings plausible to the reader. And as this civilization builds its history and legends, there's an anti-parallel in the human story thread: they've devolved civilizationally, losing much of the expertise, technology, even the language of their pre-collapse ancients.
This book is not the same caliber as Cixin Liu's Three Body Problem. But it is far better than the last sci-fi novel I read, Andy Weir's readable but forgettable Project Hail Mary.
Update: I've read and reviewed the two sequels to this novel, Children of Ruin and Children of Memory.
Notes:
* I can't help but think of this book as sci-fi meets The Selfish Gene.
* The idea of encoded/instinctive knowledge vs. learned knowledge: as these accelerated species develop self-awareness, they struggle to figure out ways to pass on learned knowledge.
* This spider civilization is (massively) female dominant: a female can kill a male at any time for any reason, and males are eaten alive after copulation. Eventually however, the spider culture develops a sort of men's rights movement: one of the spiders becomes sort of a male Elizabeth Cady Stanton, advocating for male spider rights. It's a cute conceit running alongside the main story.
* The ant civilization on this "accelerated evolution" planet at first acts like a gigantic siafu, devouring everything in its path across entire continents.
* The humans here are descended from far more advanced ancient, pre-collapse humans; human beings of the future are hypocognizant, they hardly understand anything about the technology the ancients used, they have to use a "classicist" to read old Earth tech manuals, etc.
* Some of the dialogue is Scalzi-esque: trendy language not appropriate for an operatic novel.
* A too easy ending? "The two peoples of the green world work together in easy harmony now."
Vocab:
Abseil: rappel; descend a rock face or other near-vertical surface by using a doubled rope coiled round the body and fixed at a higher point
Conurbation: an extended urban area, typically consisting of several towns merging with the suburbs of one or more cities
Chivvying: tell (someone) repeatedly to do something
Oubliette: a secret dungeon with access only through a trapdoor in its ceiling
Seraglio: women's harem in an Ottoman palace.
Lazar house: hospital for persons with infectious diseases (especially leprosy)
Counterpane: bedspread
Idiolectic: the dialect of an individual person at one time. This term implies an awareness that no two persons speak in exactly the same way and that each person's dialect is constantly undergoing change--e.g., by the introduction of newly acquired words