It's been 20 years since April 20, 1999, when two high school students, Eric Harris and Dylan Klebold, spent the final 49 minutes of their lives killing their classmates at Columbine High School, Columbine, Colorado. 12 students and 1 teacher were killed, and many others injured, and Harris and Klebold committed suicide. This infamous event has been forever seared into our nation's memory, and has had effects on our lives. It is THE watershed mass school shooting in America. BUT school shootings have continued apace since Columbine. Mass murders have continued. What were the motives of Harris and Klebold, and other mass shooters; what can we learn from Columbine; how can we reduce school shootings; what to do about the trauma experienced by survivors and a nation? Dr. Frank Farley is a professor at Temple University, Philadelphia; former President of the American Psychological Association, the Society for the Study of Peace, Conflict and Violence, the Society for Media Psychology and Technology, the American Educational Research Association, and Chair of the National Violence Summit (see YouTube). Phone (215)668-7581   email: frank.farley@comcast.net