Tushnet argues that the writing of non-commercial fan fiction is fair use. Fair, because it takes the source material as raw material and creatively transforms it in ways that copyright law is meant to encourage – for example, by expanding covert meanings perceived to be present or implicit in the original text, presenting new interpretations and viewpoints, or reflecting critically on the original content – and because it is extremely unlikely to substitute economically for, or damage the market of, the original work. “Like a book review that quotes a work in order to criticize it, a retelling of a story that offers the villain’s point of view or adds explicit sexual content can be a transformative fair use,” she maintains.
But there is an opposing view that considers fan fiction to be insufficiently transformative. Although the characters may be harnessed to a different story vision, or even set in an alternative universe, fan fiction is essentially a narrative reworking with key fictional elements of the original; a derivative work, not a critical work, unlike a book review. In this view, copyright owners are entitled to protect their characters against fans’ distortions.