Silicate Glasses and Melts, Second Edition describes the structure-property-composition relationships for silicate glasses and melts from a geological and industrial perspective. Silicate melts and glasses at high temperature and pressure are responsible for mass transfer in the Earth via formation and movement of molten silicate. It is the principal process by which the Earth was formed and evolved. These processes are responsible for volcanic activity, formation of new crust, some earthquake activity, and transfer of materials to form economically viable ore deposits. In materials science, glass, which results from cooling of melt to near room temperature conditions, can serve as a proxy for melt. Glass also is a fundamentally important component of a range of materials science and engineering applications. The new edition of Silicate Glasses and Melts, 2e not only describes, discusses, and updates information that may have resided in the literature for some time, but also introduces new information (concepts, data, and interpretation) that have developed since the first edition was published in 2005. Updated information includes (i) characterization of silicate melt and COHN fluid structure (with and without dissolved silicate components) with pressure, temperature, and redox conditions and how structural variables respond to chemical composition, (ii) determination of solubility and solution mechanisms of COHN volatiles in silicate melts and minerals and of solubility and solution behavior of silicate components in COHN fluids, and (iii) effects of very high pressure on structure and properties of melts and glasses.