Third in the ST Destiny series.
Everything comes to a head in this one. Including finding out where the Borg actually came from in the first place. I did see the Borg origins coming from a ways off, but it seemed fairly obvious so I think it was probably supposed to be figured out fairly early on. And it was good to finally have an answer to that particular question.
The massive amount of devastation is heart-breaking. Entire planets that have been part of the Trek universe for a long time are gone or severely damaged.
There's generally been a "status quo" kind of philosophy to ST books. Major things don't change. It's really interesting seeing that philosophy change.