Knut Hamsun was a Norwegian writer who was awarded the Nobel Prize in Literature in 1920. Hamsun's work spans more than 70 years and shows variation with regard to consciousness, subject, perspective, and environment. He published more than 23 novels, a collection of poetry, some short stories and plays, a travelogue, works of non-fiction, and some essays.

Hamsun is considered to be "one of the most influential and innovative literary stylists of the past hundred years". He pioneered psychological literature with techniques of stream of consciousness and interior monologue, and influenced authors such as Thomas Mann, Franz Kafka, Maxim Gorky, Stefan Zweig, Henry Miller, Hermann Hesse, John Fante, James Kelman, Charles Bukowski, and Ernest Hemingway. Isaac Bashevis Singer called Hamsun "the father of the modern school of literature in his every aspect—his subjectiveness, his fragmentariness, his use of flashbacks, his lyricism. The whole modern school of fiction in the twentieth century stems from Hamsun".

The young Hamsun objected to realism and naturalism, arguing that the main object of modernist literature should be the intricacies of the human mind. He described the "whisper of blood, and the pleading of bone marrow". Hamsun is considered the "leader of the Neo-Romantic revolt at the turn of the 20th century", with works such as Hunger (1890), Mysteries (1892), Pan (1894), and Victoria (1898). His later works, in particular his "Nordland novels", were influenced by the Norwegian new realism, portraying everyday life in rural Norway and often employing local dialect, irony, and humor.

Hamsun had strong anti-English views, partly due to the treatment of Norway during World War I, and openly supported Adolf Hitler and Nazi Germany, traveling to meet Hitler during the German occupation of Norway. Due to his support for the occupation of Norway and the Quisling regime, he was charged with treason after the war. He was not convicted, officially due to psychological problems and issues relating to old age, but was issued a heavy fine in 1948. His last book, On Overgrown Paths, authored in semi-imprisonment in Landvik, concerned his treatment and rebuttal of accusations of his mental ineptness.