The term "essay" refers to a piece of writing in which the author presents his or her own point of view; however, the definition is vague, overlapping with those of the words "letter," "paper," "article," "pamphlet," and "short story." In the past, formal and informal essays were subdivided into two categories: "Serious purpose, dignity, logical organisation," and "length" are the characteristics of formal essays, whereas the informal essay is characterised by "the personal element (self-disclosure, individual tastes and experiences, confidential manner), humour, graceful style, rambling structure, unconventionality or novelty of theme," among other characteristics.
Essays are commonly used for a variety of purposes such as literary criticism; political manifestos; learned arguments; observations of daily life; recollections; and personal reflection. In today's world, almost all essays are written in prose, but some poems have been dubbed essays (for example, Alexander Pope's An Essay on Criticism, and William Shakespeare's An Essay on Man). While most essays are short and to the point, enormous works such as John Locke's An Essay Concerning Human Understanding and Thomas Malthus' An Essay on the Principle of Population serve as counter-examples to this rule.
Essays have become a significant part of formal education in some countries (such as the United States and Canada). Student writing skills are improved in secondary school by teaching structured essay formats; admission essays are frequently used by universities to select applicants, and essays in the humanities and social sciences are frequently used as a means of assessing the performance of students during final exams in these subjects.
Essays have been adapted for use in a variety of formats other than writing. It is common for documentaries to incorporate documentary filmmaking styles into their work, with the focus being on the evolution of a theme or idea in the process of production. It is possible to write captions or add text to accompany images in a photographic essay, which covers a subject using a sequence of connected photographs.