The young adult genre is in an inescapable phenomenon in modern-day cinema, butt it wouldn't exist had publishers failed to realize how much money could be made with YA fiction. Thanks to the success of the Harry Potter and Twilight, every single studio is scrambling to acquire the most talked about teen fiction on the market to turn into the next billion-dollar movie franchise. Consider what's next: The Maze Runner, The Mortal Instruments, Divergent and the Delirium trilogy, with a few coming-of-age books that don't deal with dystopian themes, including the Sundance hit, The Spectacular Now, sprinkled in.

But before the genre became the go-to buzz word in Hollywood, many filmmakers had already succeeded in shaping teen books into critically acclaimed, if not beloved, movies. Here are the best of the best of them: The 25 Best Young Adult Movie Adaptations. If only those behind this year's failed franchises The Host and Beautiful Creatures took some tips from them.

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