What do you think of Conrad's "heart of darkness"?

I think that the title is very well choosed. He describes horrors in Congo during the reign of Leopold,II,king of Belgium. But, as historians we do have to be careful with that book, because it is a novel and it's difficult to know if the author describes true events or not. Many historians used that book to prove the cruauty of leopold, but I said it, it is a novel. Good readind anyway