This book brings together the latest findings on mineral and thermal waters from countries in Southeastern (SE) Europe (Croatia, Bosnia and Herzegovina, Serbia, Montenegro, Macedonia, Albania, Romania and Bulgaria). Each chapter is dedicated to the most recent geochemical and hydrogeological investigations for a specific country in SE Europe, helping readers to understand the origins and applications of mineral and thermal waters – aspects which are of great importance for the economic development of this region, as these waters are renewable resources, and have been gaining in popularity over the last few decades. Thanks to the region’s favorable geological conditions, it is home to more than 6,000 sources of mineral and thermal waters, characterized by different physical properties and chemical compositions.