Today more and more freshwater bodies have become polluted by nutrients originating from agricultural, domestic and industrial sources, and thereby eutrophied. The process of eutrophication of lakes and reservoirs is very much related to how society functions, and these societal factors are rarely comprehensively addressed together with the technical ones. This book is produced with participation of 26 experts involved with the management of freshwater resources from Africa, Europe, North and South America, Asia and Oceania. Their experiences on the causes and possible ways to prevent eutrophication have been assembled here. While this publication is not intended to be a technical manual on how to prevent or solve the problem of eutrophication, it does provide a comprehensive view of the essential components and processes to address the issue effectively.