Who is the narrator of conrad's novel that involves a boat trip up the congo river to inner station?

The novel that this refers to is Heart of Darkness by Joseph Conrad. This novel was written between 1898 and 1899 in England, based on the experiences that Conrad had had in Africa. In this novel, we find two narrators that coexist. First, there is an anonymous passenger on a pleasure ship who is listening to Marlow's story. The second one is Charles Marlow himself, who is a middle-aged ship's captain.