This book investigates the fundamental properties and response of materials in extreme environments such as static and dynamic high pressure, high strain and high strain-rates, high radiation and electromagnetic fields, high and low temperatures, corrosive conditions, environments causing embrittlement, and environments containing atomic oxygen. This is an extremely active and vibrant field of research, in particular because it is now possible to create laboratory conditions similar in pressure, temperature and radiation to those found in planetary interiors and in space. In addition, advanced simulation methods, coupled with high-performance computing platforms, now afford predictions - on a first-principles basis - of the properties of materials in extreme environments. Scientists from a broad spectrum of fields are represented, including space science, planetary science, high-pressure research, shock physics, ultrafast science, and energetic materials research.