In his 1978 book The Act of Reading, Iser provides an account of what happens in the mind as a reader approaches literature. He argues that reading is a fundamentally dual process, consisting of both active and passive components. Critics, with much encouragement from Wallace, have tended to imagine the reader as engaging only in what Iser dubs "passive syntheses," or the experience of getting swept along by a story. This experience must be supported, however, by the active component, in which the reader produces the story under the guidance of the text. Such activity is necessary because literature differs from biography, or any other fact-based narrative genre, in its deliberate isolation from the way things operate in the external world. Instead of having recourse to a common reality that the audience shares with both writer and characters -- so that all are parts of the same network, and what happens in the story maintains a link with "actual events" -- a novel must establish for the reader how the world between its covers operates. Because nothing in the world of the novel is given, what Iser calls a "fundamental asymmetry between text and reader" exists, in which the text guides, but only the reader can fill in the missing background if communication is to be succesful.