[SS.I 4.0] This is an exploration of the issue of influence among school shooters, documenting references by subsequent attackers to those who came before them. It also notes historical figures who may have served as role models for violence. The bulk of the document is a listing of school shooters and their influences. For an analysis of the multiple types of influence among school shooters, see the article “Different Types of Role Model Influence and Fame Seeking Among Mass Killers and Copycat Offenders.” For a graphic representation of the influence of Columbine on subsequent attacks, see “The Influence of Columbine.” [This “information” document includes incidents up to 2017; we hope in a future revision to extend the coverage up to the present.]