Born John Griffith Chaney in San Francisco, London was the son of an astrologer who deserted his family. He quit school at the age of 14 and spent the next decade wandering North America and the Pacific. He went to Japan as a sailor, rode the rails in America as a hobo, spent time in jail for vagrancy, and headed to the Klondike during the gold rush.

Determined to make a living as a writer, he approached it as a trade, and found his way into print with his tales of Alaska. His novel Martin Eden (1909) describes the determined and disillusioning uphill climb he made out of the "Social Pit" from poverty to society. London hit the big time with the success of The Call of the Wild in 1903 and became the highest paid writer in the United States. Still, London was no spendthrift, and had to write for money for the rest of his life.

Thought of by many as a mere adventure writer, the best of his realistic and often horrifyingly blunt cautionary tales of the wilderness only rarely descend into sentimentality. His most interesting works explore the gray area between civilization and the wild, chronicling the adventures and self-discovery of protagonists like Martin Eden and Buck in Call of the Wild who straddle the boundary between both worlds. London’s experiences with poverty, toil, and prison made him a militant socialist, and his ideas informed much of his work, especially his nonfiction and journalistic writing. His book The Iron Heel (1908) is a chilling prophecy of fascist tyranny.