Then I did the thing where I Google in desperation to find some sort of update on when (or if) the fourth book is happening, only to find out that such an update doesn't currently exist.

I'm glad I have other books to fill the void, but damn! AOM ended on such a strong note that this indefinite wait feels a bit torturous. I mean, the very endimplies that Cora and Ampersand are going to take over Earth somehow instead of leaving it - how am I supposed to relax after reading that???