In 1969, Michel Foucault gave a lecture titled "What is an Author?" in which he laid out his theory on the definition of the relationship of "author" and text and reader. His main argument is that the author has been removed from critical theory by Barthes and Derrida, who declare the author "dead," because critical theory of their era analyzed text only, with no reference to the originator of the text:
criticism and philosophy took note of the disappearance – or death - of the author some time ago ... [because] the task of criticism is not to bring out the work's relationships with the author, nor to reconstruct through the text a thought or experience, but rather to analyze the work through its structure, its architecture, its intrinsic form,... (Foucault, "What is an Author," generation-online.org)
Literary critical opinion changes with time and this extreme exclusion of the originator of a text is not so adamantly held as is witnessed by Wayne Booths'e ethical criticism ("The Company We Keep").
Foucault posited an "author function" that related to society, exclusivity to literary works (as opposed to scientific works that are strictly limited by the factuality of the text), the question of attribution of origination of a text, and the "persona" that replaces the originator and is similarly vaguely defined as the "narrator persona" is vaguely defined.
...the author does not precede the works; he is a certain [author] functional principle by which, in our culture, one limits, excludes, and chooses; in short, by which one impedes the free circulation, the free manipulation, the free composition, decomposition, and recomposition of fiction. (Foucault)