This edited book is based on the accepted papers for presentation at the 1st MedGU Annual Meeting, Istanbul 2021. With three sections spanning a large spectrum of geological and geoenvironmental topics, this book presents a series of newest research studies that are nowadays relevant to Middle East, Mediterranean region, and Africa. The book includes major subjects related to hydrogeology, geoecology, and atmospheric sciences. Case studies are from the fields of hydrology, hydrogeology, hydrogeochemistry and water resources, biogeochemistry, geobiology and geoecology, atmospheric sciences, meteorology, climatology, and oceanography.