Karl Stig-Erland "Stieg" Larsson was a Swedish writer, journalist, and activist. He is best known for writing the Millennium trilogy of crime novels, which were 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 U.S. (for the first book only). The publisher commissioned David Lagercrantz to expand the trilogy into a longer series, which has six novels as of September 2019. 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.

Stieg Larsson was born in Skelleftehamn, Västerbottens län, Sweden, the son of Erland Larsson (born 1935) and his wife Vivianne, née Boström (1937–1991). His father and maternal grandfather worked in the Rönnskärsverken smelting plant in Skelleftehamn. Suffering from arsenic poisoning, his father resigned from his job, and the family subsequently moved to Stockholm. However, because of their cramped living conditions, they chose to let one-year-old Larsson remain behind. Until the age of nine, Larsson lived with his grandparents in a small wooden house in the countryside, near the village of Bjursele in Norsjö Municipality, Västerbotten County. He attended the village school and used cross-country skis to get to and from school during the long, snowy winters in northern Sweden, experiences that he remembered fondly.