This powerful retrospective analysis of the aftermath of the 1999 Columbine High School shooting considers society's response to the attack, the long-term implications of the shooting, and the ways in which research and related policy must continue to move forward.

• Analyzes the broad cultural impact of the Columbine High School shooting

• Reviews changes in police responses that have developed since the day of the attack

• Examines warning signs that pre-dated the attack and how threat assessment has advanced to preclude similar tragedies

• Explores legislative responses in the aftermath and why they were not successful

• Considers the lessons learned in the 20 years after the shooting and how they can be used to prevent future acts of mass violence