On 22 July 2011 Anders Behring Breivik killed 77 of his fellow Norwegians in a terrorist atrocity that shocked the world. Many were teenagers, just beginning their adult lives. In the devastating aftermath, the inevitable questions began. How could this happen? Why did it happen? And who was Anders Breivik?

Asne Seierstad was uniquely placed to explore these questions. An award-winning foreign correspondent, she had spent years writing about people caught up in violent conflict. Now, for the first time, she was being asked to write about her home country.

Based on extensive testimonies and interviews, One of Us is the definitive account of the massacres and the subsequent trial.

But more than that, it is the compelling story of Anders Breivik and a select group of his victims. A picture emerges of a killer - isolated, awkward, with a strange and troubled childhood. And on the other side, we come to know fascinating, dazzling young people such as Simon Saebo and Bano Rashid, eager to contribute to their society. As we follow the path to their inevitable collision, it becomes clear just what was lost in that one day.

A gripping, shattering and vital book, One of Us is the story of a massacre and a study of evil. But it is also a story about community versus isolation, hope versus rejection, love versus bigotry - and a powerful memorial to those who lost their lives.