Much progress has been made in elucidating the complex structures of silicate glasses and melts. X-ray and neutron scattering, spectroscopy, and theoretical calculations now provide a reasonably clear picture of many aspects of the short-range structure of glasses (which approximates the melt structure at the glass transition temperature). Critical effects of redox conditions and volatiles on structure have been clarified. Qualitatively, links between structure and properties such as molar volume, entropy, cation partitioning, and viscosity have been established, but quantitative connections remain challenging. Effects of temperature and pressure on structure have been the subject of much recent work.