What is the main thing that distinguishes literature from escapist literature?

The main object that distinguishes theses two types of reading comes down to the opinion of many stuffy old English teachers that have a preference to cracking a book open to find dust and moth colonies rather than one of clean pages and occasionally trivial, albeit whimsical, literature adventuring.

Or perhaps it is mainly determined by time, subject matter, and the fact that people give books awards and stamps of significance to ones they like.

Really, what is a good book to you is entirely up to what you think.

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Though perhaps all the "escapism" required for the aforementioned teachers is sustained in so-called "classic literature"; adventure and youthful frivolity in The Adventures of Huckleberry Finn and euphoria and love in Wuthering Heights...