The global geochemical cycles of volatile elements (e.g., H, C, N, S, halogens, and noble gases) are critical for understanding the dynamics, state, and evolution of Earth and other planets' deep interiors (i.e. mantles and cores) through time. All planetary events and processes would have been involved with those volatiles, including early accretion and differentiation, magma ocean formation and solidification, core formation, magma generation and volcanic eruption, hydrothermal alteration, tectonics and subduction processes, and atmosphere development. Volatiles, in turn, profoundly influence physical and chemical properties of planetary materials, such as elasticity, melting, phase relation, viscosity, rheology, diffusion, and thermal and electrical transport properties within planetary interiors. As such, deciphering feedbacks between those deep processes and volatiles is of paramount importance to exploring the past, present, and future of planetary habitability. This session seeks to interact perspectives from the interdisciplinary communities of mineral physics, petrology, geochemistry, geophysics, and theoretical simulations.