In fiction and nonfiction, structure helps writers progress from one set of ideas and events to the next, producing consistent themes that recur throughout the composition. For example, in J.K. Rowling's "Harry Potter" series, the main character is an orphan who lives in two worlds and often feels alienated in both environments. The sequential structure of the books juxtaposes Harry's different environments, surrogate families and similarities to the villain to explore themes of homelessness, sacrifice and finding acceptance.
Structure provides the framework for writers to lay out the details of a story and determine when to introduce and resolve conflicts. Outlines are a common tool for planning the structure and preventing a story from straying too far from the central themes or final resolution. For example, fiction writers typically use the beginning of a story to define the main character's traits before the onset of a major conflict, which provides a solid structure to justify how the character behaves when the situation changes.
In analytical nonfiction, such as critical essays, structure makes it easier for writers to describe the basic details of another author's work before presenting their own questions, criticisms and conclusions. Analytical works typically have a thesis, which provides a reference point for the themes the writer intends to include throughout the argument.