Book excerpt: The approach that should be used by law enforcement officers in order to safely and effectively enter a room is a point of contention among many police trainers. Based on five experiments conducted over a two-year period, Evaluating Police Tactics demonstrates that the conventional wisdom is not optimal. Using the scientific method to systematically assess current room entry philosophies and techniques employed by police, Evaluating Police Tactics offers suggestions for examining the current philosophies and determining how patrol officers can enter scenes of ongoing violence, find the shooter, and stop the killing as safely and effectively as possible. About the Real-World Criminology Series More than just textbooks, the short books in the Real-World Criminology series are designed to be of interest to particular fields within criminology. They can be policy primers, spurring innovations in policing and corrections, theoretical works dealing with policy implications, or program evaluations incorporating theoretical foundations. Each book covers something that is happening –or should be happening—in the world of criminal justice.