The essay is an essentially rhetorical genre, in which the author need not defend his or her views in a rigorously logical manner, nor justify conclusions with formal disciplinary support. Rather, the essayist gives a personal, reasonable, informed opinion on subjects of common and usually immediate interest, to a literate public. As such it is a literary form particularly suited to the dissemination of ideas, controversy, and the critique of ideology. There are a variety of types of essays (historical, philosophical, topical) and related subgenres and modes (treatise, newspaper article, autobiography, meditation, confession). It is best to think of the essay not as a predetermined form but rather as a variable model of communication between writer and public that reflects the expressive needs and particular ideological agenda of the author and which, depending on literary quality and degree of intellectual richness, complexity and sophistication, may transcend its immediate purpose and achieve the status of a classic.