Active shooter events are occurring much more frequently and happening in all size communities. It is the responsibility of agencies to try to prepare for violent acts. Based on personal experience from being in command of active shooter event (ASE), discussions with other systems after an ASE, and study of other events, this lecture will cover keys for lessons learned, preparing for an event, response and command, and recovery from the event. The presenter was in command of operations on July 7, 2016, the night Dallas police officers were ambushed by a gunman who killed 5 officers and injured several others.