This course introduces the student to a wide variety of diffusion-controlled phenomena in solids and liquids. Solids covered include inorganic and organic glasses; glass-ceramic; ceramics; metals; and porous materials. Liquids covered include oxide and non-oxide glass forming melts; halides; and liquid metals. Both atomistic and mathematical approaches to diffusion processes will be emphasized. The course will include extensive discussion of measurement techniques and will deal with diffusion of both ionic and gaseous species. Diffusion under stress; thermal and electrical field gradients will be discussed in addition to diffusion under concentration of gradients.