This book covers everything. Nice strageties to defeat the toughest enemies and shows you how to unlock the paradox endings as well as the hidden ending. Without this book I would not have been able to even come close to realizing what this game has to offer. (Typical RPG)
Usually, I don't get hardcover guides but this one was actually cheaper than it's paperback counterpart when I purchased it.
The "Tour Guide" section was what I ended up using the most. This section gives you hints, tips and tricks on how to aquire fragments, and shows enemy data, for any given map.