In Heart of Darkness, Polish-British author Joseph Conrad deploys atmosphere, ambiguity and nuance to spin a languid tale of intrigue and madness in late 19th-century Colonial Africa. The story's narrator, Marlow, tells of a trip up the Congo River to rescue a legendary ivory trader, Kurtz, from a mysterious illness. Considered Conrad's masterpiece, and one of the greatest novels of the 20th century (it was written and serialized in 1899 but not published in book form until 1902), others have condemned the dehumanizing depictions of Africans as racist and outdated.