"I"

At the end of City of Glass I was extremely confused. To me it seems that the author Paul Auster is doing exactly what Don Quixote did in his life adventure. The four main character are actually one person, but who is the "I"? The entire book is told in third person except for the last two pages where the story take a turn and begins being told from the first person point of view. I'm confused at which for of the main character it is being told from. 

We know that Paul Auster is there but is he with Quinn, Work, or Wilson? From the story we get a sense that Work's character died sometime when he was living in the alley watching the Stillman's apartment. Quinn could be the second person but if he is than why would he wish himself luck? The last possibility is that Wilson could be the second person because he does not want to read the  red notebook. This is just like Quinn becuase he doesn't want to hear about the opinions of the girl that reads his book while waiting for Stillman to get off the train. Overall, we will never know who the "I" is but it is interesting to think about each main character being that "I".