Part I: History of Water on Mars -- Climate Evolution and the History of Water on Mars -- Hydrated Minerals and Magmatic Water -- Lacustrine Environments -- Early Life on Earth and Analogies to Mars -- Part II: Water on Present Mars and Potential Habitats -- Water Distribution in the Atmosphere and Soil and the Global Water Cycle -- Cold Region Hydrology and its Analogy for Mars -- Life in Ice and Cold Regions and Implications for Mars -- Groundwater -- Groundwater Microbiology and Application to Mars -- Brines, Halophiles and Evaporites in Permafrost -- Hydrothermal System in Impact Craters and Impact Crater Microbiology -- Microbiology in Hydrothermal Systems and Deep Subsurface. Growing evidence, based on observations from orbiters, landers and telescopes, indicates that Mars may still have numerous hidden water reservoirs. Moreover, from the point of view of habitability, Mars is a prime target for astrobiologists in search of extant or extinct microbial life because we know that life exists in earth's permafrost regions, such as parts of Siberia and the Antarctic, which are the closest terrestrial analogues to Mars. "Water on Mars and Life" surveys recent advances made in research into water on Mars together with its astrobiological implications. This volume addresses not only scientists working in the field but also nonspecialists and students in search of a high-level but accessible introduction to this exciting field of research.