Coordination has been identified as an essential prerequisite for a swift and effective response to major incidents, whether natural or man-made. Recommendations in efforts to link together the various agencies needed for responding to critical incidents are outlined as keys to effective coordination and include: preparedness and prevention, exercises and training, and response. Any critical incident creates enormous challenges for law enforcement agencies. Critical incidents that require the response of several emergency response agencies increase the challenges. Working together within a common framework, developing emergency operations plans, and exercising against those plans will not eliminate all the challenges, but will place law enforcement agencies in a position to anticipate and manage the challenges. The Federal Government has done its best to generate guidelines for response. But, many State and local emergency response agencies, feeling an urgent need for agreed-upon standards for coordination, have initiated the coordination process themselves. What they have accomplished can serve as a model for other agencies’ coordination efforts. This report presents the guidelines, recommendations, and models that came to light as a result of the executive sessions held by the Police Executive Research Forum with the support and guidance of the U.S. Department of Justice, National Institute of Justice. Appendixes A-E