The novel is centred on a dual pattern of oppositions and contrasts (outer/inner, light/darkness, civilization/savagery, good/evil) which often contaminate one another. This means that nothing is pure and well-defined.

The most rational part is represented by Marlow

The rules are forgotten. The most instinctive part surfaces and leads him to evil (he turns into a terrible, ruthless monster and greedy man)

MULTIPLE POINTS OF VIEW: reality is split into several truths, as every character gives his/her own version of the story. There is not only one truth, there are many. The vision of the world is subjective. The reality is fragmented (CALEIDOSCOPE of each individual points of view)

TIME MANIPULATION: there are shifts backwards and forwards in the narration, which recall the workings of our mind. Such fracturing of time implies a more subjective perception and anticipates the modernist novel

SOLEMN AND COMPLEX STYLE ; IMPRESSIONISTIC AND SYMBOLIC METHOD: a wide use of contrasting symbols and images (light/dark, civilized/uncivilized) builds up a web of light and shade

In the late 19th century most European countries were engaged in a feverish race for expansion which they considered firstly as a way to spread civilization and secondly as a means to gain enormous profit trough the exploitation of the lands and native populations

Heart of Darkness is the denunciation of the evils of colonialism Conrad had seen. He unveiled the betrayal of the "great cause" (White's man burden - Kipling → "to seek another's profit and work another's gain") and the exploitation of natives. Colonization is nothing but exploitation.

A crew of 5 members is on board a ship on the river Thames. Marlow, one of them, tells the others the story about the encounter between him and Kurtz, a famous colonizer. Marlow is sent by his company to take him back to civilization. In fact, without any rules, the most instinctive part surface and lead Kurtz to evil. However, Kurtz dies insane before being "rescued".

Marlow's is also a journey into the self, into the dark region of the Freudian subconscious made up of dreams. While the most rational part surfaced in Marlow, the most instinctive one took over Kurtz.

The Africans represent the dark force of ignorance

Attack against colonialism. Kurtz embodies the contradictions of imperialism, based, in theory, on the liberal ideas of progress, but, in practice, on robberies and the exploitation of Africa.