The novel explores events in the fictional town of Commonwealth, Washington in 1918 during World War I and the Spanish flu epidemic.

The town agrees to quarantine itself from the outside world, hoping to escape the international epidemic of the flu.

The politics of the Industrial Workers of the World, American Protective League, and the Four Minute Men, as well as the aftermath of the Everett Massacre, play major roles in the novel.

According to the author's afterword, he created the fictional community of Commonwealth inspired by his studies of Gunnison, Colorado (which imposed a quarantine trying to prevent the flu) and the socialist communes in Washington state of Equality Colony, Freeland, and Home.

This novel won the James Fenimore Cooper Prize for Best Historical Fiction in 2007.