The convergence of profit, public, nonprofit and social organizations constitutes an increasingly important reality that has been labeled the fourth sector. This movement brings together talents, resources, and skills from governmental and non-governmental partners, corporations, and civil society at large to leverage well-being responses and develop new approaches to address social challenges. The diversity and complexity of these problems heightened by the COVID-19 pandemic call for a collective social effort and innovative solutions. Despite the growing importance and initiatives taking ownership of community well-being through fostering partnerships in which different stakeholders share responsibilities to build a better future and common good, this is an under-researched area. This edited book discusses the challenges and opportunities of the emerging fourth sector, and features selected papers from XXI International Congress on Public and Nonprofit Marketing (IAPNM 2022) held at the University of Minho in Braga (Portugal) in July 2022.