Hayley’s diary symbolizes one’s unknowability; one can never be sure that one truly knows and understands another person. It is also a motif that points to The Importance of Feeling One’s Feelings. Ella is “surprised by the choice” of a plain, black book (47), expecting the Hayley she knows to have covered the front with stickers instead. In an attempt to rationalize her desire to read her best friend’s most private thoughts, Ella thinks, “There’s nothing in there she wouldn’t have shared with me anyway. Right?” (47), a question that foreshadows the fact that the book contains any number of—and perhaps only—thoughts and feelings that Hayley never shared with Ella. When Sawyer once joked about reading Hayley’s diary to see what it said about him, Hayley spoke uncharacteristically sharply, claiming that she needed “one place [she] c[ould] dump everything. Everything. Even [her] darkest, most vile confessions, without thinking someone might judge [her]” (47). This description of the book’s contents seems hyperbolic, like Ella’s comparison of the diary to the One Ring of Power, an allusion to J. R. R. Tolkien’s Lord of the Rings trilogy. Ella thinks that, in Hayley’s eyes, someone acquiring access to the book and its contents “would destroy [Hayley’s] universe” (47).