It's very difficult to read a book that treats cultures and people so harshly, but then again this happens in numerous books from this time period, and even now book still carry those themes over. The prejudice that can be found in so much literature at this point is almost heartbreaking, to know that these people are solely treated as savages, workers, or just means to an end. The pictures above are postcards from Conrad's expedition into the Congo on behalf of Belgium. The steamboat in the upper right parallels the one in the novella, the line of black men being seemingly judged on their "strong" appearance is reminiscent of the labor that they're going to have to do for a country that wants only their natural resources and to colonize them. No one had known the culture or the tribes there yet they tried to take over, to force them to be "civilized" on the European standard. They wiped out cultures, languages, and hurt so many innocent people. 

There is much to be said about the fear of the unknown and how it drives men to madness, in action or in thought. To our main character, Charlie Marlow, his trip in the Congo fascinated him. He said that "We were wanderers on a prehistoric earth, on an earth that wore the aspect of an unknown planet. We could have fancied ourselves the first of men taking possession of an accursed inheritance..." (Heart of Darkness 62). The land had looked untouched and unbothered but it was taking care of a people that generally respected the earth and gave back to it. They believed themselves entitled to the land even though they were well aware they were not it's only inhabitants. On page 28, when Marlow's aunt was talking about his journey she mentioned "weaning those ignorant millions from their horrid ways". They thought themselves better than the indigenous people and so they believed that they were owed something by them. They even had a whole group of people that made an International Society for the Suppression of Savage Customs to take away what the natives had built. While it is harder to draw parallels to a science fiction story, this same sense of superiority can be seen from Frankenstein onto his Creation. Even though this Thing had developed it's own conscious and learned how to survive on it's own, Victor still thought of it as his own, as something to fear. He only knew and liked the creation during the process of making him, once the Creation got free and did things of his own liking, Victor feared it. Fear of the unknown persists throughout both of these novels. Marlow didn't know how the native tribes worked, unlike Kurtz who even had relations with one of the women and knew generally what he was doing, thus Marlow was terrified for most of the journey.

Fear of the unknown is a very powerful tool. It can drive men to take control of people that once had free will and put them on a path towards what the "conquerer" deems worthy.