Award-winning Norwegian journalist Åsne Seierstad's book “One of Us: The Story of Anders Breivik and the Massacre in Norway” examines the incidents of July 22, 2011, when one man’s attacks left more than 70 people dead. In this conversation with NYPL’s Jessica Strand, Seierstad discusses violent extremism — and how a society copes with the reverberations of homegrown evil still felt today.