This reference book is made up of currently 26 individual Synthesis Papers (SPs) generated by the OpenNESS members. The individual SPs have been formally consulted within the entire OpenNESS consortium and hence represent an agreed document for OpenNESS defining and elaborating on essential ideas linked to the ecosystem service concept. All SPs have been gone through an editorial process including approved revisions. The consultation was handled for the consortium in a transparent way, e.g., the consortium could see how authors responded to the comments/criticism on the original drafts. These consultation documents were available to al partners on the OpenNESS extranet. Some SPs were followed up and published in journals