You could write a book about a landing on Mars in which a landing on Mars is a metaphor for something that is going on now. You could also write a book about a landing on Mars that’s a landing on Mars.
“The rules of thumb with which we approached our music: Repeating a musical phrase the same way twice needs a hell of a better reason than a-a-b-a form. Never do anything confused that can be done simple. Never do anything dull that can be done interesting.”
Samuel R. Delany | Heavenly Breakfast