How does Conrad tread the theme of colonial exploitation in Heart of Darkness?

Theme of Imperialism

The theme of the evil of imperialism lies at the centre of the novel,  Heart of Darkness . Perhaps Joseph Conrad's main objective in this novel is to show the imperialism explanation of a backward country by a civilized nation . Conrad's treatment of this theme was inspired mainly by his own visit to the Congo and his exploration of that dark country.

The keynote of the theme of imperialism may be traced at the very beginning of Marlow's narration.  The conquest of another country , says Marlow, mostly means the taking away all things from those who have a different complexion.  Marlow's (Conrad's himself)experiences in the Congo clearly show that the whitemen there failed to perform their duties . Instead of civilizing the savage natives the whitemen turned into exploiters. The Congo was at that time being governed by the Belgian king Leopold II,  and the Belgian Trading Company was sending its agents into the Congo for trading purposes.Ivory was the chief commodity they sought for. Later on, we see that ivory not only dominates that thoughts of Mr. Kurtz , the agent of the Belgian Trading Company  but also has become an obsession with him.  The ivory symbol the whitemen's greed and commercial mentality . Their ivory symbol the whitemen's  greed and commercial mentality .Their chief concern in the Congo is to collect ivory , although they profess that they have come to civilize the natives . Nowhere do we find any mention of any service being rendered by these whitemen to the natives of Congo.

A glorious example of evil and selfishness we find in Mr. Kurtz.  He has begun to identify himself with the savages . Instead of improving their way of life,  he has himself become a savage in their company.  Actually  Heart of Darkness portrays in nutshell the deceit,  robberies , murder, slave trading and general policy of cruelty of the Belgian rule in the Congo.  Conrad in this novel not only exposes the hollowness and the weakness of the Belgian imperialist rule over the Congo but also reminds us of the British imperialism in various countries of the world of his time. 

To sum up, the Belgian Trading Company went to the then dark continent,  "the Congo" to civilize the natives there . But ironically they became uncivilized and brutish for material gains.  They turned out to be seasoned schemers and plotters.  Joseph Conrad conveys his strong disapproval of these whitemen to us most effectively and his purpose is to raise in us the greatest possible contempt for these whitemen.