Water is the essential substance for life on Earth. The natural patrimony of all living beings and the material and cultural heritage, a common good, a shared resource, a treasure trove of humanity. The nature of water, water at rest and in motion, the water cycle and its management are addressed here in a multidimensional, comprehensive and transdisciplinary approach. The book focuses on water without complying with any disciplinary approach: philosophical, historical, physical and mathematical issues are merged with traditional hydrochemistry, hydrostatics, hydrodynamics and hydrology to provide an overview of basic knowledge on Earth-s water. These five lectures can be delivered to any undergraduate STEM student to introduce them a valuable, basic, multidisciplinary knowledge on water. Non-specialists will find here an insight of water made as simple as possible, but not simpler than required
