Reactions between fluids and rocks have a fundamental impact on the geodynamics and geochemistry of the Earth at all scales. Fluids strongly affect the petrophysical properties of rocks, enhance mass transport and the kinetics of reactions. Therefore, they play an important role in geological processes from the Earth’s surface to processes deep within the lithosphere. Although it is widely known that fluids are essential for metamorphism, metasomatism and deformation, their effects and underlying mechanisms as well as the rates of processes are still poorly constrained. In addition, the quantitative understanding of the role of fluids on large-scale mass exchange between Earth’s reservoirs remains limited. The combined use of metamorphic geology with both micro- (e.g., crystallographic orientation analysis, X-ray and electron tomography, atom probe tomography, nanoSIMS, etc.) and macro-structural observations, geochronology (i.e., U-(Th)-Pb), thermochronology (i.e., K-Ar, Ar-Ar, (U-Th)/He), stable isotope geochemistry (i.e., H, O, C, Li), laboratory experiments and numerical modelling has allowed to quantify the mechanisms, timing and rates of fluid-rock interaction and deformation in the lithosphere. We invite multidisciplinary contributions that shed light on the coupled processes of fluid flow, chemical reaction, deformation and fluid-mediated mass transport occurring at all scales in the lithosphere. We also encourage presentations that cover all aspects of the deep cycling of volatiles (hydrogen, carbon, sulphur, nitrogen, noble gases, halogens), from subduction zones to the deep mantle, in the field of experimental/theoretical/natural fluid geochemistry, thermodynamics, petrology and geodynamics.