Sufficient emergency resources are essential for emergency services to provide timely help to affected people and to minimize damage to public and private assets and the environment. Emergency services, however, face resource shortages and increasing demand over time. As a result, their response times increase, resulting in lower survival chances of affected people and more severe damage to properties and the environment. Thus, emergency services need to utilize and effectively manage all their available resources. These can be divided into traditional resources, such as ambulances, and new and emerging resources, such as volunteers. Models and methods developed using operations research (OR) methodologies can facilitate the management of these resources. However, despite a rich literature on OR-based models and methods focusing on traditional resources, the literature on new and emerging resources, and specifically volunteers, is scarce.The aim of this thesis is to develop models and methods for task assignment and dispatch of volunteers to daily medical emergencies. This also includes forecasting models for future emergencies. The developed models and methods consider volunteer programs in Sweden and the Netherlands, employing real historical data.The aim has been addressed through three studies, one main study and two substudies, the results of which are presented in the six included papers. The main study focuses on the development of models, methods, and strategies for task assignment and dispatch of volunteers to out-of-hospital cardiac arrest (OHCA) cases using OR.To evaluate the survival rates of these patients, the most important health outcome of a response process, survival functions have been used in the development of these models and strategies. The results of this study are presented in Papers Ⅱ-Ⅴ. The first sub-study investigates different types of new and emerging resources used in daily medical emergency response, and the results are presented as an overview of the literature in Paper Ⅰ. The second sub-study focuses on the forecast of medical emergency demand, and its outcomes are presented in Paper Ⅵ.The overall conclusion is that the use of OR-based models and methods can contribute to improved outcomes and increased survival probabilities compared to the strategies and techniques used in the existing systems. vi vii This PhD journey has been a roller coaster ride with many ups and downs. At times, the upward stretches were long and slow while the downward ones were deep, feeling as though they would never end. Despite all the challenges along the way, it was a very enjoyable experience, giving me the opportunity to learn many lessons and grow. It would not have been possible to finish this roller coaster ride and write this thesis alone; I have been lucky to have had many people with me throughout this time, cheering me on, helping me, and supporting me, to whom I am sincerely grateful.First and foremost, I would like to thank my supervisors, Tobias Andersson Granberg, Jan Lundgren, and Anna ...