Knut Hamsun (born Knud Pedersen on 4 August 1859, passed away on 19 February 1952) was a Norwegian writer who was awarded the Nobel Prize in Literature in 1920. His literary career spanned over 70 years, during which he showcased tremendous variation in consciousness, subject, perspective, and environment, publishing more than 23 novels, a collection of poetry, short stories, plays, a travelogue, works of non-fiction, and essays.

Hamsun is heralded as "one of the most influential and innovative literary stylists of the past hundred years" (ca. 1890–1990), pioneering psychological literature with techniques such as stream of consciousness and interior monologue. He significantly influenced authors including Thomas Mann, Franz Kafka, Maxim Gorky, Stefan Zweig, Henry Miller, Hermann Hesse, John Fante, James Kelman, Charles Bukowski, and Ernest Hemingway. Isaac Bashevis Singer lauded Hamsun as "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."

His early rejection of realism and naturalism in favor of exploring the intricacies of the human mind, advocating for literature to describe the "whisper of blood, and the pleading of bone marrow," positioned Hamsun as the "leader of the Neo-Romantic revolt at the turn of the 20th century." Noteworthy works include Hunger (1890), Mysteries (1892), Pan (1894), and Victoria (1898). His later "Nordland novels" reflected Norwegian new realism, portraying everyday life in rural Norway with local dialect, irony, and humor.

Hamsun's life was not without controversy. His strong anti-English views, stemming partly from the treatment of Norway during World War I, and his open support for Adolf Hitler and Nazi Germany, including a visit to meet Hitler, cast a shadow over his legacy. Following World War II, due to his support for the occupation of Norway and the Quisling regime, Hamsun was charged with treason. He was not convicted, officially due to psychological issues and aging, but was fined heavily in 1948. His last book, On Overgrown Paths, written in semi-imprisonment, concerned his treatment and rebuttal of accusations of mental ineptness.