I think that a good case can be made that nostalgia forms much of the novel. If nostalgia can be seen as a romanticized view of being in the world, then it is to a great extent that Hamid's work centers on nostalgia. Changez possesses a nostalgic view about America when he first enters. It is a notion of "the West" that those outside of it have had for a great deal of time. This nostalgia is rooted in the idea that "the West" is the best and everything else is subservient. It is a nostalgia that ensures people from other parts of the world place themselves in a submissive position in order to gain acceptance into places like "America."
Erica is obviously driven into nostalgia after the September 11 attacks, plunging into an idealized and unattainable view of her relationship with Chris. This nostalgia romanticizes the past in light of an uncertain future, which is exactly how Changez views America's actions in the wake of the September 11 attacks. In this construction of nostalgia, a romanticized view of America's past is embraced. It is a World War II vision where the nation gallantly strode into battle against belligerent nations to achieve victory and domination. Finally, nostalgia can be seen in Changez's embrace of fundamentalism, something that he believes has "the answer" in an idealized view of the world. In each setting, nostalgia, an idealized and romanticized construction of being in the world, is chosen over the difficult and insecure condition of the present tense. Nostalgia is chosen over reality, and why these choices are made forms the crux of the novel's identity. It is for this reason that it is to a great extent that it is about nostalgia in different forms and contexts.