In terms of literary movements, Heart of Darkness is often cited as a transition into modern realism. First appearing in print in 1899 as a magazine serial, it was then published in novel form in 1902 as part of a collection of Conrad's work. It has been referred to as a novel that acts as a bridge between the Romantic literature of the 19th Century and the modern realism of the 20th Century. In its stark depiction of the stupidity, cruelty, and greed of colonial policies inflicted upon native populations, the novel creates a narrative of realistic, often shocking detail. It focuses upon the inner life of its protagonist, Charlie Marlow, but not in the manner associated with Romanticism; instead it explores Marlow (and his antagonist Kurtz) in terms of the human psyche. The influence of Sigmund Freud's revolutionary modern theories of the unconscious self is readily apparent in the novel. Other literary techniques, such as the complex structure and point of view, moved the novel into the realm of modern realism and foreshadowed the work of important 20th Century writers that followed.