Since June 1999, the U.S. Department of Education and the U.S. Secret Service have been working as a team to try to better understand--and ultimately help prevent--school shootings in America. The authors believe the results of this effort have given schools and communities real cause for hope. Through the "Safe School Initiative," staff from the U.S. Department of Education's Safe and Drug-Free Schools Program and the U.S. Secret Service's National Threat Assessment Center have found that some school attacks may be preventable. In particular, the "Safe School Initiative" findings indicate that incidents of targeted violence in school were rarely impulsive; that the students who perpetrated these attacks usually planned out the attack in advance--with planning behavior that was oftentimes observable; and that, prior to most attacks, other children knew that the attack was to occur. This document takes these findings one step further by setting forth a process for identifying, assessing, and managing students who may pose a threat of targeted violence in schools. This process--known as threat assessment--was first pioneered by the U.S. Secret Service as a mechanism for investigating threats against the president of the United States and other protected officials. This "Guide" represents a modification of the Secret Service threat assessment process, based upon findings from the "Safe School Initiative." It is intended for use by school personnel, law enforcement officials, and others with protective responsibilities in the nation's schools. This "Guide" includes suggestions for developing a threat assessment team within a school or school district, steps to take when a threat or other information of concern comes to light, consideration about when to involve law enforcement personnel, issues of information sharing, and ideas for creating safe school climates. An appendix provides annotated resources. (Contains 21 footnotes.) [This guide is an update of the 2002 report, "Threat Assessment in Schools: A Guide to Managing Threatening Situations and to Creating Safe School Climates" (ED466013).].