the book is called Fallout: The Wanderer.

Its a prequel to fallout 3 telling the story of your grandfather. and how james grew up to be a scientist. theres more to it of cource but i hope it will peek intrest umunst fallout 3 lovers that seek for more backstory. anyway i hope i actually write it all and hope i get some people to buy a copy. well thats all. bye!