Heart of Darkness by Joseph Conrad

The reaches opened before us and closed behind, as if the forest had stepped leisurely across the water to bar the way for our return. We penetrated deeper and deeper into the heart of darkness.
As the peak of European Imperialism, steamboat captain Charles Marlow travels deep into the African Congo on his way to relieve the elusive Mr Kurtz, an ivory trader renowned for his fearsome reputation. On his journey into the unknown Marlow takes a terrifying trip into his own subconscious, overwhelmed by his menacing, perilous and horrifying surroundings. The landscape and the people he meets force him to reflect on human nature and society, and in turn Conrad writes revealingly about hypocrisy, morality and the dangers of imperialism.

“Heart of Darkness” is an eminent instance of the literary evocation of evil, and we can see how it might be regarded as a representation of the concept of original sin in fresh and secular terms. —T. S. Eliot
The heavy hypnotic style [of “Heart of Darkness”] falls around me again, and I am aware of the poverty of my own. —Graham Greene
One of my favorite books. —William Faulkner
Conrad endeavored to create a great, massive, multiphase symbol that would render his total vision of the world, his sense of individual destiny, his sense of man’s place in nature, his sense of history and society. —Robert Penn Warren