Humans play an undeniable role in the acceleration of threats to the diversity of ecosystems, species and genes. This book is a response to the urgent need of policy oriented socio-ecological research, profoundly based on empirical evidence. Socio-environmental patterns and political responses are compared through the use of case studies analyzing a range of pressures to biodiversity. Aquatic bioinvasions in the Ebro River and Lake Izabal exemplify socio-environmental processes linked to river basins. Other cases examine processes at the regional level: the social attitudes to genetically modified organisms in Catalan agriculture, the implementation of a Regional Strategy for Biodiversity in the I^le-de-France, the management of an invasive insect in the city of Paris, and the comparative analysis in Kent (UK) and Tartu (Estonia) county of the effects of the Common Agricultural Policy on pollinators’ diversity. An economic valuation of the decline of pollinators in Germany and Spain, and an analysis of land use changes in the new EU member states focus on processes at the national scale within the EU frame. A case study in Argentina, about the emergence of pesticide resistance in an invasive pest, embodies the relationship between a national state and the processes of the world economy. The ALARM project aims to promote creative thinking. Inspired by ecological economics, methodologies employed range from multi-criteria evaluation and participatory techniques to social network analysis, valuation of environmental services, scenario modelling and historical analysis. The authors have uniquely explored case-study-based research for socio-economic analyses of biodiversity risks. Emphasis is put both on the lessons learnt from the comparative analysis as well as on the methodological innovations.