What surprises the man in the library What does it mean that Gatsby knew when to stop What does Nick say about New York?

The man in the library is surprised to discover that Gatsby's books are real, and not just for show. Gatsby's ability to know when to stop symbolizes his self-control and ability to rein in his desires and aspirations when necessary. Nick describes New York as a city that offers both the vibrant excitement of limitless opportunity and the underlying corruption and moral decay that permeate society.