Coast lines have been and still are the centre lines of civilization around the world with still increasing pressure from both sides, the hinterland and the sea, with all its foreseeable and unforeseeable impacts given by nature or mankind. While response of nature to such impacts is flexible in the way that all morphological changes with all the consequences are tolerated as part of the system, man cannot tolerate short-term or long-term changes without being threatened in its physical and economical existence. The objectives of this Advanced Research Workshop (ARW) on Environmentally Friendly Coastal Structures were: - to contribute to the critical assessment of existing knowledge in the field of coastal and environmental protection; - to identify directions for future research in that area; - to promote close working relationships between scientists from different countries and with different professional experience. Latest trends in research in coastal and environmental protection have been summarized and developed during the meeting. Seventeen papers are presented in this book, attempting to cover as completely as possible all related aspects - coast, engineering structures, water, sediments, ecosystems in their complicated interaction.