While not an actual character, Alice personifies her diary—she calls it "Diary," as many people who keep diaries do, but she refers to it as her friend and writes to it in a conversational style as if she were speaking to it. It is the repository of all her thoughts and the only thing that travels with her through her journey—from her carefully noted first diary at home to dateless scraps of paper on the road to cryptic descriptions from a mental hospital. Alice seeks most of all someone to talk to, and the diary fulfills this better than any person, promoting her expressive prose style with its ever- ready blank page. She feels she hides her identity when with others, but with Diary, she can be her true self. As she gets further into the counterculture, drugs supplant the diary as the focal point of her life, but she always maintains her devotion to it. The diary's triumph comes at the end since Alice discards it in favor of wanting to share herself with other people—the tool that enables Alice to better communicate and understand herself has served its purpose.
The diary also functions as the engine for Go Ask Alice's epistolary narrative (a narrative composed of letters). The epistolary novel, especially one in which the protagonist addresses only herself, allows us deeper insight into the character's emotional world. Many novels, in particular coming-of-age works, use some kind of device to allow a first-person narrative that does not seem as if the protagonist has somehow magically transcribed his thoughts to a page—note Holden Caulfield's revelation that he has been telling his story to a psychiatrist in The Catcher in the RyeGo Ask Alice, whether or not it is a true diary as it claims, accomplishes this task and makes it all the more real and immediate through the diary.