Erik Larson is an American author and journalist from New York who specializes in the genre of historical nonfiction. He was born in 1954. His works—including The Demon of Unrest­­—often intermix in-depth archival research with an accessible storytelling style that brings historical events to life for a popular audience. Larson is best-known for The Devil in the White City, which juxtaposes the 1893 Chicago World’s Fair with the life and crimes of a serial killer.

To a greater extent than in some of his other narratives, Larson uses The Demon of Unrest to draw parallels to modern political tensions, especially to the American political unrest that led to violence surrounding the electoral college certification of President Joe Biden in 2021 (See: Background). Larson highlights these parallels to present his historical events as having continued relevance in the present day.

Major Anderson was the US Army commander who led the garrison of Fort Sumter after South Carolina seceded from the Union. He was in his early fifties during the events of the Civil War. Anderson was deeply religious and devoted to his family; he had a wife—Eba—who suffered from a chronic health condition, as well as three daughters and one son, who was also named Robert.