Theme and Theme Statement

Theme is the central idea or universal truth that the story examines

A theme statement is a single sentence that attempts to explain this truth (what the story worries about).

Such a sentence meets these criteria:

Is a generalization about life or human nature using universal terms
Accounts for all the details of the story (doesn't look at only one part)
Avoids clichés or plot summaries
May recognize the significance of the story's title or special symbols