The marine and coastal ecosystems of the Baltic Sea are exposed to an intensifi[1]cation and diversification of anthropogenic activities and related environmental pressures. Human interest in marine resources and space often overlap with environmental protection objectives, causing conflicts. Research can assist capacity building to enable knowledge-based decision-making in marine management and policy to help solve these issues. Three participatory systematic maps were carried out on marine and coastal ecosystem services (ES), monetary and non-monetary valuation methods applied to value them, and the interrelation of ES and human health and well-being in the Baltic Sea region. Policy advisors were engaged throughout the review process. The aim was to map existing scientific knowledge and identify knowledge gaps for the scientific communityand to support the implementation and update of the key marine protectionpolicies in the region. This chapter introduces the review methodology, providesan overview of knowledge gaps and missing links in ES research, and addressesfuture steps to connect the dots.