Beginning his restless wanderings again, he worked as a goldminer in the Klondike, Yukon Territory (1897–8). Returning to San Francisco, he began to sell stories, novels, and non-fiction, much of it drawing on his experiences in the North. The best known of these are The Call of the Wild (1903), The Sea Wolf (1904), and White Fang (1906). In 1902 he visited the slums of London, and this inspired his book The People of the Abyss (1903). In 1904 he covered the Russo-Japanese War for the Hearst newspapers, and in 1914 he covered the Mexican Revolution for Collier’s. In 1907 he went to the South Pacific in a small sailboat, a trip described in The Cruise of the Snark (1907). His peripatetic life was the major source for his fiction, especially his thinly autobiographical novels, Martin Eden (1908–9) and John Barleycorn (1913). From 1905 on he was based on his large ranch in Glen Ellen, CA, but he often travelled on the lecture circuit.

His work earned him over a million dollars, but he never seemed able to deal with his success; he promoted explicit Socialist views in both fictional and non-fictional works, even while exalting the life of the primitive and self-sufficient. He became an alcoholic and by 1909 was plagued with a variety of ailments. Dependent on painkillers, he died from a (possibly self-inflicted) overdose of morphine.

See also American literature, novel.