In April 1999, we were all stunned by the news that Eric Harris and Dylan Klebold had attacked and killed students at Columbine High School in Littleton, Colorado and, more recently, in December 2012, that Adam Lanza, after killing his mother at home, then massacred twenty-six staff and students at Sandy Hook Elementary School in Newtown, Connecticut. These events evoke dread of potential events, a quest to understand why they occurred, and ways to avoid further comparable killings.
