An essay is a piece of writing from an author's personal point of view that can be fictional or non-fictional. The document discusses the typical structure of an essay, including an introduction that introduces the topic, a main body with the key points, and a conclusion that reviews the main ideas. It also describes four common types of essays: narrative essays that tell a story, descriptive essays that paint a picture, expository essays that provide facts and analysis, and persuasive essays that aim to convince the reader of a viewpoint.