Children of Memory, by Adrian Tchaikovsky

Finally got around to reading this on Saturday. Book 3 of the Children of Time series, sequel to Children of Time and Children of Ruin. Previous books set up the Rus-Califi virus that gave sentience to spiders and octopuses, both on their own terraformed worlds (spiders on Kern's World and octopuses on Damascus), with one book dedicated to each. This book breaks the mold by introducing two new terraformed worlds (Rourke and Imir), introducing a new sentient (the corvids) that has not been created or even touched by the Rus-Califi virus, and having the focus of the book be not on the corvids, but on something introduced in the previous book: the Nod organism.

( spoilers )

All in all, I'd say this was not as good as Children of Time, but better than Children of Ruin. (I really did not appreciate the octopuses.) I'm not sure if a fourth book is in the works, but I think one obvious path would be to have either a second of the alien engines or some other structure/relic from them, being encountered by one of the terraforming teams/an uplifted Earth species; later Earth colonists optional.

(P.S. Adrian, if you're reading this? Slime molds would be cool. Please steal.)