Karl Stig-Erland "Stieg" Larsson was a Swedish writer, journalist, and far-left activist. He is best known for writing the first trilogy in the Millennium series of crime novels, which was published posthumously, starting in 2005, after he died of a sudden heart attack. The trilogy was adapted as three motion pictures in Sweden, and one in the United States (for the first book only). Larsson had conceived of ten books in the series; the publisher commissioned David Lagercrantz to write the next trilogy, and Karin Smirnoff to write the third trilogy in the series, which has eight novels as of December 2025. For much of his life, Larsson lived and worked in Stockholm. His journalistic work covered socialist politics and he acted as an independent researcher of right-wing extremism.
He was the second-best-selling fiction author in the world for 2008, owing to the success of the English translation of The Girl with the Dragon Tattoo, behind Afghan-American novelist Khaled Hosseini. The third and final novel in the Millennium trilogy, The Girl Who Kicked the Hornets' Nest, became the bestselling book in the United States in 2010, according to Publishers Weekly.