John Griffith "Jack" London was an American novelist, journalist, and social activist. A pioneer in the then-burgeoning world of commercial magazine fiction, he was one of the first fiction writers to obtain worldwide celebrity and a large fortune from his fiction alone, including science fiction.
Some of his most famous works include The Call of the Wild and White Fang, both set in the Klondike Gold Rush, as well as the short stories "To Build a Fire", "An Odyssey of the North", and "Love of Life". He also wrote of the South Pacific in such stories as "The Pearls of Parlay" and "The Heathen", and of the San Francisco Bay area in The Sea Wolf.
London was part of the radical literary group "The Crowd" in San Francisco and a passionate advocate of unionization, socialism, and the rights of workers. He wrote several powerful works dealing with these topics, such as his dystopian novel The Iron Heel, his non-fiction exposé The People of the Abyss, and The War of the Classes (font: Wikipedia).