Like tying up loose threads.
This book is short stories that basically answer every question you might have left like; wanting to know more about how Cinder became a cyborg, or how Wolf became Wolf, all these and more are answered. Even things you may have overlooked. There is a story for each of them and it gives you more insight into who they are and their importance to the series.
I loved it, of course. I love the whole series.
Seriously, I'm bummed beyond words at it being over but also feel I got closure. You don't get that all the time in a series. You do here though.
If you haven't read the series, what the hell are you waiting for?!