Why would a student bring a weapon to school and without any explicable reason open fire on fellow students and teachers? Are school shooters angry? Are they crazy? Is their motive revenge? Hatred for the victims? A hunger for attention? The origins of human violence are complex. Thinkers, historians, and scientists have explored the issue for centuries, but answers remain elusive. The roots of a violent act are multiple, intricate, and intertwined. The mix of factors varies according to the individual and the circumstances. Understanding violence after it has occurred is difficult enough. Trying to assess a threat and keep it from being carried out is even more of a challenge. This book presents a systematic procedure for threat assessment and intervention.