A computer narrative is a story told on a computer. This story need not be wholly or at all textual. While some traditional narratives have been converted to the computer medium, interactive narratives, to which the reader can explicitly react, reveal a new potential of this medium. To emphasize their most important attribute, these works are called interactive fictions. The input of the reader can influence the events of these stories, the reactions of the characters, and even the locales visited and their condition. Interactivity substantially affects the basic components of the narrative. The interface controls the reader's interaction with the narrative. It can be text-based (e.g., the reader types a response) or graphical (e.g., the reader points and clicks) or contain elements from each category. The advent of interactive fiction that consciously attempts to be literary urges the investigation of how different types of computer narrative interfaces influence the reader's actions, what narrative possibilities different interfaces reveal or exclude, and how different interfaces affect the ability of a work to be literary. While different interfaces are suited to interactive fictions in different media, an interface that is consistent, engaging, and uniform within the media of the interactive fiction has many advantages. To best unlock the literary potential of this form, the interface should also allow interaction at every moment and should convey the meaning of the interactor well enough for him or her to serve as a co-author.