An intercalary chapter (also called an inner chapter, inserted chapter, or interchapter) is a chapter in a novel or novella that is relevant to the theme, but does not involve the main characters or further the plot. Intercalary chapters often take the form of vignettes that offer a broader or alternative perspective to the experiences of the main character. They can also be used to provide social and historical background that can't be easily interwoven into the narrative chapters.