Picked this book up on Amazon a few months ago, it's an awesome book. I'd have loved it if they had done one for Gears 2 with Operation Hollow Storm, the Gears 2 in game Collectables story as a physical collectors item would have been incredible.
It was written by the writer of the game but never confirmed if it was actually canon. I take it as canon unless stated otherwise because I can't see any conflict with the universe and it gives us some awesome Baird character stuff!