This book emphasizes and presents the latest information on eco-physiology and biochemistry of cyanobacteria with special emphasis on their biodiversity, molecular mechanisms of some important biological processes and survival mechanisms under myriad of environmental conditions as well as bioremediation. Cyanobacteria are the most dominant prokaryotic floras on the Earth¿s surface, and are of great importance in terms of ecological, economical and evolutionary perspectives. They are oldest groups of photosynthetic autotrophs, which create oxygenic atmosphere for the development and sustainability of ecosystems with different life forms. The book presents an integrative approach to their possible biotechnological application in the field of bio-energy and various aspects of biochemistry,