Describe symbolism in City of Glass by Paul Auster

As a meta-narrative element, Paul Auster the author writes himself into the story, both as a writer and as a detective. This means that although the reader might have been supposing the writer himself intended to be the narrator, actually, he has created a thinly veiled other person, eventually named Daniel Quinn. His inclusion as a character in the book represents the difference between the artist and the narrator.