This book aims to evaluate and identify the most sensitive resources or key resource of south Red Sea lagoons, Egypt. This is an initial step in insuring provision of appropriate types and levels of tourist uses. A diagrammatic sketch to indicate the different habitats or organisms was done for each lagoon. However, a profile to show the stratification and abundance of different habitats or organisms at different lagoon depths was done. Beside the general description of each lagoon characteristics with respect to different stratifications, data were also provided in such a form suitable for GIS mapping.Sensitivity of each lagoon was evaluated according to five major important criteria which are diversity, rarity, fragility, naturalness and size. The keywords of each criterion and a brief description of its use were described