In this volume, the distribution, speciation, and behavior of sulfur in various natural environments, ranging from planetary cores to atmospheres, is covered over a series of 18 comprehensive chapters. They treat topics encompassing a variety of geological materials from sulfur-bearing minerals to hydrothermal fluids to silicate melts, and processes involving sulfur that operate under different terrestrial regimes, from the core to the surface and ultimately to the atmosphere. The role of sulfur in extraterrestrial environments, including asteroids, comets, the Moon, Mercury, Venus, Mars, the gas giants and their moons, as well as extrasolar gas giants, is covered in several dedicated chapters. This book provides a comprehensive up-to-date survey of the role of sulfur in geological processes on both terrestrial and extraterrestrial scales.