As Special Legal Counsel for the National Center for Interstate Compacts it was both an honor and a privilege to serve as a principle compact drafter and member of the EMS National Advisory Panel to provide the legal framework, build consensus, and advance the national dialogue that made the United States EMS Compact a reality. It was also a privilege to assist in convening the inaugural meeting of the Interstate Commission for EMS Personnel Practice on October 10, 2017 in Oklahoma City. ​ Interstate compacts are not widely understood, although the EMS compact and other health occupational licensure compacts mentioned in this Guide have resulted in unprecedented use of compacts in a wide range of interstate regulatory purposes including licensure of EMS personnel. As science and technology have enabled people to travel the country virtually as well as literally. Such mobility has also increased the need for accommodating the need for health practitioners licensed across state lines to provide competent health care commensurate with the rapidly changing laws and regulations concerning the provision of telehealth to our highly mobile society. As this Guide demonstrates, “clinicians often cross state lines, not as an exception but as part of their day-to-day work, disaster response, or military service. The EMS Compact ensures clinicians can do so legally, safely, and efficiently without sacrificing public protection or clinical oversight.” This Guide also illustrates that a national crisis such as the Covid-19 epidemic requires a licensure process in which “compact member states could immediately recognize EMS licensees from other Compact states for the first time without requiring additional applications, processing delays, or redundant fees.” A process which once took weeks was now needed to be instantaneous and as the result of the EMS compact, clinicians were quickly deployed across state lines with the legal authority to practice. Donnie Woodyard has provided a comprehensive analysis of the EMS Compact, including chapters on How the EMS Compact Functions, Disaster Response and Mutual Aid, EMS Data Privacy and National Security, and Advancing the EMS Compact Together. His experience, knowledge, and insights give us an invaluable look from the inside and the impact of the EMS Compact on member states and the nation. This Guide is an extraordinary resource for those involved in EMS work including clinicians and regulators, as well as legislative and executive branch officials and I am grateful that this definitive work has been made available. ​ ​ Richard L. Masters, J.D. has also been the primary drafter of many multistate licensure compacts including Nursing, Medicine, Physical Therapy, and Psychology. He also provides legal advice to a variety of compact governing boards and testifies about compact legislation before state legislatures and the U.S. Congress. Rick is also a co-author of both the ICAOS Bench Book cited herein and the only current legal treatise on interstate compacts published by the American Bar Association entitled The Evolving Law and Use of Interstate Compacts, 2nd Edition.