Earth, water, air and fire: According to the ancient Greek philosopher Empedocles they are the elements of all matter. Indeed the three main spheres of our natural environment are mainly made of earth (lithosphere), water (hydrosphere) and air (atmosphere). This book ideally completes the Empedocles' set of elements by reporting on recent applications to earth, water and air of such a modern fire constituted by the laser source. Lithosphere, hydrosphere and atmosphere play a major role in sustaining life on our planet. All the biogeochemical cycles take place on them or are part of the matter exchange among them. A thorough understanding of such global processes requires powerful tools.