The document discusses the three main purposes an author may have for writing: to persuade, to inform, or to entertain. It defines each purpose and provides examples. It encourages readers to consider the author's purpose when analyzing a text by asking questions about the intent and techniques used. The key purposes are to persuade by convincing the reader of a viewpoint, to inform by providing factual information to educate, and to entertain by telling an interesting story for enjoyment.