He was the first author to write about the working class and the first great Danish communist writer. He was born to a large family in a very poor area of Copenhagen, Denmark. After a short career as a worker, he attended a folk high school; later, he worked as a journalist. In the mid-1890s he travelled in Southern Europe, and his book Soldage (1903) is largely based on those travels. Probably his best known and most translated book is Pelle Erobreren (Pelle the Conqueror), the last volume of which was completed in 1910. His other great work was Ditte Menneskebarn (1917-21), a hailing of the working woman and her selfsacrifice as a mother of others. The much debated Midt i en Jærntid, 1929, (i. e. In an Iron Age, eng. transl. In God's Land) satirises the Danish farmers of World War I. During his last years he wrote a (never fulfilled) trilogy (Morten hin Røde, Den fortabte generation, Jeanette 1944-56) which was partly a continuation of Pelle the Conqueror, partly a masked autobiography.

    Combining elements of the serial film, detective story and gothic horror novel, Kzradock is a surreal foray into psychoanalytic mysticism.Opening in a Parisian insane asylum where Dr. Renard de Montpensier is conducting hypnotic séances with the titular Onion Man, the novel escalates quickly with the introduction of battling detectives, murders and a puma in a hallucinating movie theater before shifting to the chalk cliffs of Brighton. It is there that the narrator must confront a ghost child, a scalped detective, a skeleton, a deaf-mute dog and a manipulative tapeworm in order to properly confront his own sanity and learn the spiritual lesson of the human onion.When Gershom Scholem read the novel in its 1912 German translation on the recommendation of Walter Benjamin, he concluded: “This is a great book, and it speaks a formidable language … This book lays out the metaphysics of doubt.”