Who am I ? Is the theme of the novel. If I am 1 person to my friend D and 1 person to my friend S am I 1 person or 2 persons? Extrapolate this out for many people...1 , None, 100,000.

It is on the same vein as something a teacher said in high school. If you are always losing memories and gaining new memories are you the same person now as you were yesterday?

It's a thought provoking book.