A prologue is an introductory section of a literary work, often found in books, plays, or poems. It sets the stage for the main story by providing background information, context, or insight into the characters and themes. Prologues can help readers understand the setting and tone before diving into the narrative. In theater, a prologue may be delivered by a character or narrator, offering a preview of the plot or themes. This device is commonly used in works like Shakespeare's plays, where it prepares the audience for what is to come. Overall, prologues enhance the reader's or viewer's experience by establishing a foundation for the story.