I read the book a long time ago, but I was unable to stomach the movie when his on-screen surrogate started physically beating his on-screen wife so I walked out. I think it was about 8 minutes into the movie. The book was no great shakes. I heard from someone that some of it was fiction written by a friend.
Well Graziano did say when he and Jake where kids he was so unpopular no other kids would go looking for him in a game of hide and seek aha.