Joseph Conrad's Heart of Darkness has a Stanley type character- Kurtz. The character Kurtz also has elements of other people Conrad had met or knew of during his stay in the Congo. The film Apocalypse Now was loosely based on the book. Conrad does indeed get to the heart of the darkness that drove these men. There was a psychologically complex nature to Stanley which explains why he was driven by more than just a lust for recognition etc it was something central like a sublimated sexual passion.