High-pressure materials research has been revolutionized in the past few years due to technological breakthroughs in the diamond anvil cell (DAC), shock wave compression, and first-principles molecular dynamic simulation (MD) methods. Pressure-induced chemistry and high-pressure synthesis of superhard materials were topics of the successful Symposium DD, High-Pressure Materials Research, held at the 1997 MRS Fall Meeting in Boston. Since then, a plethora of discoveries have been made, including new materials synthesized under high pressure, geophysical-geochemical material conversion and ionization prior to polymerization of molecular solids. Additionally, new experimental and computational techniques, such as in situ studies of materials properties and transformations using laser heating are increasingly providing a deeper insight and a few surprises for the behavior and properties of matter at elevated pressure conditions. This book provides a timely report on progress in the field. Topics include: synthesis and characterization; disordered systems; dense molecular materials; and properties under extreme conditions.