Water is a scarce resource today and even more so in the near future. On many of the Mediterranean Islands the demand for water exceeds the supply, a tendency that is going to worsen in view of anticipated climate change. How is this scarce resource going to be distributed among the many user groups: agriculture, tourism, private households and industry? How did previous generations deal with this problem, and what would be strategies for a sustainable and equitable water management in the future? These and many other questions were discussed by 24 graduate students from 12 different European countries as part of the SUSTAINIS advanced study course of the Centre for Environment Research at the University of Muenster. The present volume is based on the lectures delivered and the student contributions presented during "SUSTAINIS - Sustainable Use of Water on Mediterranean Islands".