This Handbook has been developed in the framework of the ThinkNature project. Its main objective is to gather and promote state-of-the-art knowledge regarding Nature-Based Solutions (NBS), comprising a comprehensive guide to all relevant actors. To this end, each aspect of NBS is investigated, from project development to financing and policy making, and is presented in a concise and comprehensive way, in order to be easily understandable. Specifically, the Handbook is highly recommended to all stakeholder groups that use NBS in their work, but it can also be useful for other organisations and individuals that comprise potential NBS stakeholders. Additionally, many chapters can contribute to increasing public awareness about NBS. In respect of the structure of the Handbook, each chapter focuses on a separate issue (analysed and documented through specific subtopics) and targets different types of NBS stakeholders. In general, Chapters 1-4 provide general background knowledge, useful for everyone involved in NBS initiatives; Chapters 5-7 are more specialised, addressing issues relevant to different NBS stakeholder groups (i.e. Chapter 5 for research and innovation, Chapter 6 for business sector, and Chapter 7 for policy sector); and Chapter 8 concludes with key recommendations.