Book excerpt: School of Errors establishes another voice in the discussion of how to promote safe schools. It challenges the unchecked expansion of school fortification and questions the realized benefit of inter-agency collaboration during a sentinel event. This book offers an alternative to traumatizing simulations by providing clear options for improving school safety by the empirically-proven effective measures of leakage detection (preventive) and sensemaking (reactive). School of Errors restores the scientific method to school safety and clears a path through the media rhetoric fogging this vital topic.