Chile is a privileged country in terms of water resources, with an average annual runoff of approximately 50,000 m3/person. However, water availability varies enormously in space, as less than 1,000 m3/person are available for more than 50% of the population. The temporal and spatial distribution of water resources is driven by processes highly variables across a country with different climates explained not only by a large range of latitudes (from 17° to 56° south), but also the presence of the Pacific Ocean and the Andes with peaks up to 7000 m. This geography makes of Chile a true natural laboratory in which water is essential for the society and the economy of the country. The relevance of water resources for the country has become even more significant in the context of a mega-drought that has affected practically the entire territory in recent years, although large floods such as those in Atacama 2015 and 2017 also take place periodically. This unique book brings together the state-of-art knowledge about the hydrology of Chile and its water resources, with a particular focus on quantitative aspects. The chapters are prepared by many of the most relevant researchers and practitioners working in water resources in the country. High-quality research contributions on climate and meteorology, surface and subsurface hydrology, water quality, water monitoring, water resource and global change, among other issues, are presented in this unique book, which offers a useful guide for academicians, researchers, practitioners and managers dealing with diverse water-related issues in Chile and other regions with similar characteristics.