It looks like it will just be a written story which will tell about the events in the games that have been officially given a place in the timeline. So probably not all games will be mentioned, and i doubt the timeline discussion will be resolved with this book.
On a sidenote: I really really hope this book will make it to Europe, I would very much like to buy it. But since it will already be pretty limited in Japan, i doubt the book will get translated and cross the borders. But, one can hope...