The exchange of volatiles (hydrogen, carbon, nitrogen, sulphur, noble gases and halogens) between the Earth’s surface and its interior controls the composition and evolution of the atmosphere and the solid Earth on geological timescales. With Earth’s active plate tectonics, cycling of volatiles is extensive, depending on the relative efficiency of volatile incorporation into the solid earth via subduction, sequestration into the mantle and core, or outgassing via magmatism and volcanic eruption. This controls the ability of our planet to develop and sustain a stable life-supporting atmosphere and oceans. Understanding the speciation, compatibility, behaviour and storage of volatiles in the deep Earth and their exchange with Earth’s surface is of critical importance for the evolution of planet Earth as we know it today. In this session, we will explore geochemical, geophysical and geodynamic processes that control the inventories of reservoirs of deep Earth volatiles. We invite contributions in a board range of areas, including volatiles in subduction processes, volatiles in the deep mantle (LLSPVs, plume source, mineralogy etc.) and the role of core/mantle partitioning on light elements in the core. Studies using petrological evidence, experimental approaches and computational mineral physics are welcomed, alongside other approaches.