Metamorphic rocks preserve a record of the processes that dictate the long-term physical and chemical evolution of the lithosphere. These processes in turn affect global-scale phenomena of broad interest, including volatile cycling over geologic time, seismicity and volcanism, the transport of elements of societal interest (e.g., rare Earth elements, lithium, copper), lithospheric deformation, and the formation and destruction of supercontinents. These processes are complex, and operate over a broad range of length and time scales. In this session, we invite contributions utilizing (and integrating) field, analytical, modeling, and/or experimental techniques to highlight the significance of metamorphic rocks in understanding Earth processes and their scientific and societal implications. We welcome contributions working at a range of length scales (from minerals to continents) and a variety of tectonic settings, including subduction zones, rifts, and continental orogens.