For some reason, this book is told in reverse order. At first, it makes you think Book was Alliance all along. Then you find out that before that, he was a Browncoat and infiltrated the Alliance and brought them their worst-ever defeat. Because of that, to me it felt like it negated the Firefly episode where the Alliance is so quick to help him. If this is what happened with the Alliance in his past, why would they be so quick to help him?
Other than that, good backstory, nice art, and it's crazy to know that we never really knew his real name.