Admittedly, I've never even glanced at a concept art book such as this, and definitely not one for a game I'd never played; but I've been anticipating this game since I first heard about it. When I saw this on NetGalley I immediately requested it.
There is some great art in this book, and it only makes me more excited for the game - which I've managed to log about 40 minutes in - but it also has a lot of MAJOR SPOILERS for the game. So if you haven't played, you're definitely going to learn some things about characters that you might not have wanted to know previously. I began skimming so I could look at the pictures by the time I was spoiled for the second time.
However, before that I loved learning the little tid-bits about how they developed the story, and why the changes of the evolution of the characters. Because the best thing to speak for this book is the art itself, I'll end this with those.