What is dystopian fiction? It's opposite of utopia, which is a perfect future world!

• Dystopian societies are undesirable or even horrifying.
  
• Dystopian societies are usually futuristic and fictional.
  
• Dystopian depictions can be regarded as warnings.
  
• Dystopian fiction is both about today and tomorrow.
  
• Dystopian fiction comments on our own society.
  
  
  ***Wikipedia as source***
  Some of the best? (Older) War of the Worlds, The Giver, Brave New World, 1984, Farenheit 451, Planet of the Apes
  (Newer) Hunger Games, Maze Runner, Matched (one of my favorite bks) Gone, Incarceron