UPDATE: I have to say, I am not as jaded about Amazon's reviews after seeing that they removed all 8 reviews before mine that looked suspiciously like they were written all by the same person, giving the book 5 stars and boosting its rating.
I write this review not because I have some kind of thing against the author, but because I honestly believe that people should be warned about this book. I was given an ARC to review and was shocked at the book's content. Find my full review by Googling the title and "mockingjay".
While the other glorious reviews praise how much this book is about The Hunger Games, let's get real here. The book is BARELY about The Hunger Games. The chapter on Tributes is about Spartacus. The chapter on weapons is a disgusting how-to on how to kill a person. The chapter on torture gives you disgusting accounts of botched executions by electric chair, describing frying skin, eyeballs popping out of sockets, and other disgusting details that don't directly relate to the book.
It reads like a textbook on the details behind the world of Panem but does NOT mention anything about district specialties, whether you really can eat pine and what it does for you nutritionally, compiled facts about characters, or a theoretical map of Panem. These are things I would expect and want in a Hunger Games Companion, but they are nowhere to be found in this book.
If you want to hand your 14 year old a book telling you how to make exploding arrowheads, how to properly hold an axe, and how to kill someone with a spear, by all means, this is the book you're looking for. Otherwise, wait for the official one. I know I almost vomited reading this book.
And on that note, examine the suspicious activity on the reviews on Lois Gresh's books. If you look at the 5 star reviews on her Twilight Companion, which got completely ROASTED by that fandom, they're mostly from anonymously protected kids under 13 with perfect grammar or people who ONLY review Lois Gresh books. All the reviewers preceding mine have only reviewed Lois Gresh books.