Magmatic volatiles (H2O, CO2, S, Cl, F, etc.) play a key role in magmatic processes and volcanic eruptions. Their progressive exsolution and ability to form gas bubbles upon decompression condition the physical properties of melts and, hence, their dynamics of ascent and crystallization. Moreover, while ultimately becoming the driving force of eruptions, the magmatic gas phase is an important source of information upon the evolution of magmatic systems thanks to both its high mobility (separate transfer or/and accumulation of gas bubbles) and its compositional dependency on pressure (differences in solubility of the volatile components). Therefore, knowing the initial dissolved content of volatiles in magmas, their behaviour during magma decompression, as well as their chemical composition and mass output at the surface is crucial to a better understanding of the dynamics of magmatic/volcanic systems. Magmatic volatiles also constitute an important matter of geochemical information upon mantle sources and magma genesis in different tectonic settings. This Session will welcome contributions covering the various aspects of magmatic volatiles transfer from the mantle to the atmosphere, including studies of volatile solubility and dissolved contents (crystal melt inclusions) in magmas, magma degassing processes, volcanic gas compositions and fluxes (crater gases, plumes and diffuse soil emanations), interactions of magmatic fluids with hydrothermal systems and crater lakes, and broader correlations between degassing, volcanic activity and geophysical signals. A central objective of that Session will be to highlight the need for integrated investigations of magmatic/volcanic systems, combining multidisciplinary approaches and different (ground-based and spece-borne) technologies.