Perhaps the most famous work of Robert Louis Steveson, fighting with Treasure Island for that title, the novella differs greatly from its adaptations by being primarily a mystery and only really confronting the duality of man and the internal moral struggle at its end. While that last bit is a huge part of the appeal of the story, the mystery itself that drives Utterson throughout the story is extremely good and makes the novella superior to all its adaptations, seeing as how the ruined twist has made a direct adaptation uninteresting. It's a very quick and gripping read and absolutely worth your time.