Although there has been little academic research on the impact of placing police officers in schools, this practice has grown substantially in response to school shootings and other violent crimes in schools. With a standardized training program since 1999, the state of Virginia has law enforcement officers working in approximately 88 percent of Virginia's 631 secondary schools. Based on this experience, the state training coordinator describes how police officers should be selected and prepared to work as school resource officers. The success of school-based law enforcement requires careful selection and specialized training of officers who can adapt to the school culture and work collaboratively with school authorities. (Contains 5 notes.)