This book catalogs the evidence based on the social, economic and environmental effectiveness of Nature based Solutions (NbS) to face environmental challenges and simultaneously provide a better understanding of associated social-ecological interactions. NbS are reframing discussion and policy responses worldwide to environmental challenges. The concept builds on and complements other closely related concepts, such as the ecosystem approach, ecosystem services, ecosystem-based adaptation/mitigation, disaster risk reduction, sponge cities, and green/blue infrastructures. The quantification of existing NbS’ effectiveness, their operationalization and replication in different environmental settings are presented here in such a way that allows them to be both widely accepted and incorporated in policy development and in practical implementation.