In the wake of this, partner management companies (Québec en Forme, Avenir d'enfant, Réunir-Réussir) have arrived as reinforcements. Since these companies only operate in a context of intersectoral cooperation and on a supra-local scale, COSMOSS is considered one of the most interesting models! Through the example of COSMOSS, this action research explains the extent to which a local community of supportive partners can be brought to work together to solve problems related to the continuity of social services. It also puts into perspective the different factors that influence this intersectoral cooperation, sometimes positively and sometimes negatively. In the end, this book is the first volume of a trilogy that aims to model and provide tools for intersectoral partnerships in the three dimensions of sustainable development. Moreover, by applying intersectorality through the axis of social development, the authors postulate that the various concepts developed can be adapted to economic and environmental partnership ecosystems.