School security is a national concern. Throughout the country, youth crime and violence threaten to undermine the safety of American students' learning environment. This handbook is the product of a joint effort of the National Association of Secondary School Principals (NASSP) and DynCorp to help educators develop plans for reducing violence in schools. It provides step-by-step instructions for assessing security at a school and for developing an individualized security plan. The introduction describes in detail the five phases of getting started--identify problems, determine objectives, evaluate measures and identify options, select options, and develop plan. The following sections offer guidelines for communicating the plan, complying with school law, responding to various incidents, and designing safe school buildings. Appendices contain a discussion of different security measures, a list of school-safety resources, a description of security-systems hardware, and a selected bibliography of 77 references. (LMI)