One of Us: The Story of a Massacre in Norway — and Its Aftermath is a non-fiction book by Norwegian journalist Åsne Seierstad.

Seierstad explains in the epilogue[1]: 514  that journalist Tina Brown commissioned her to get anything on "that man" for publication in Newsweek.

In Seierstad's words[1]: 515  she was "drip-fed the details of the planning and execution of the act of terrorism... these were drops of stories... that were tailored for the purpose of the trial."

The Hachette Book Group published One of Us: The Story of Anders Breivik and the Massacre in Norway in the UK under its Virago Imprint in March 2015.

[1]: frontmatter  Publishing rights for the Canadian and American markets were purchased – followed by an April 2015 release – by Farrar, Straus and Giroux (FSG).