The story includes many footnotes that become an essential part to understanding Colin's brain and how it works. Green says that the footnotes "function as a kind of competing narrative that comments upon and—for lack of a better word—problematizes the central narrative." "An Abundance of Katherines" is a work of fiction that includes many mathematical terms and academic language. With the footnotes and the appendix that is at the end of the novel, Green gives his readers "a way of attempting to achieve precision and clarity" of the story in general, but more specifically, Colin's mind.