This is an online officer safety and interpersonal perspectives course. This lesson focuses on preventing law enforcement officer line-of-duty deaths through maintaining vigilance. It examines what can be learned from studying data on line of duty deaths and case studies on the deaths of individual officers. The lesson focuses on communicating with dispatchers and other law enforcement officers, and anticipating potential threats. The lesson is based on a report from the National Law Enforcement Officers Memorial Fund that studied officers responding to dispatched calls for service, officers engaged in self-initiated activity (such as traffic stops), and ambushes. Based on the report, the lesson offers recommendations to help improve officer safety.