Another title for this book could be the Blue Bloods encyclopedia. It explains the background and current stories of the Blue Bloods, and of the events circulating around them. It also explains the Silver Bloods and Red Bloods.
This book clarifies any doubts one has regarding a Silver Blood, Blue Bood, or a Red Blood. Each character's story is given, which helps one understand the actions they have taken in previous books that might have gotten either them or others killed.
It also contains several astonishing facts, that will make the readers anticipate the next book even more.