Cyanobacteria are a rich source of several novel metabolites having the potential for drug development. They are a promising bioresource for application in sustainable agriculture, medicine, and green nanotechnology. Certain natural compounds of cyanobacteria such as mycosporine-like amino acids (MAAs) and scytonemin, having UV-absorbing/screening and antioxidative properties, could be biotechnologically exploited by the pharmaceutical industries for the development of natural sunscreens as well as antiaging medicines. This book encompasses the most recent knowledge and modern trends in the field of cyanobacterial research and their impact on humans. It provides a guide for beginners as well as advanced researchers in the field of cyanobacterial study.