Human civilization on it's last (eight) legs

Two civilizations on a collision course: the last remnants of humanity, crammed into a desperate generation ship in search of a new home, and an entire world of hyper-evolved spiders who got there first. What follows is a first-contact story unlike almost anything else in the genre. 
 

The novel's greatest strength is Tchaikovsky's development of the spider civilization. Rather than simply transplanting human social structures onto eight legs and calling it alien, he takes the premise seriously at every turn, letting biology drive culture, letting culture drive technology, and allowing entire developmental paths humans took for granted to be skipped, subverted, or replaced with something stranger and more interesting. The result is genuinely novel worldbuilding, rigorous and internally consistent, and the spider chapters are a legitimate pleasure to read for anyone who appreciates ideas-driven SF.
 

A problem that's not always easy to avoid in dual-narrative/POV stories is keeping the balance between the two. The spider civilization is where most of the meat is. The human storyline, by contrast, often feels like it exists to fill the gaps between spider chapters. The middle section drags in particular, and it's hard to shake the feeling that a tighter edit would have sharpened the book considerably without losing anything essential.
 

One further caveat on the worldbuilding: Tchaikovsky's commitment to detail is mostly an asset, but occasionally becomes a liability. When the novel ventures into the mechanics of certain technological developments, the specificity invites scrutiny. Some of those ideas just don't hold up. There's a version of this book where a deliberate vagueness on certain points would have been the smarter choice, allowing the reader's imagination to fill gaps rather than expose weaknesses. The broader strokes are convincing; some of the finer ones aren't. 
 

The good news is that the final act earns back a lot of goodwill. The slow burn of the middle section pays off, the two storylines converge with real tension, and Tchaikovsky finds a resolution that manages to be both surprising and thematically coherent. It doesn't entirely compensate for the pacing issues, but it does mean the book is worth pushing through on those rare occasions it starts to feel sluggish.