Preface. Groundwater -- field and experimental studies. Groundwater Evolution in an Arid Coastal Region of the Sultanate of Oman based on Geochemical and Isotopic Tracers; C.E. Weyhenmeyer. A combined isotopic tool box for the investigation of water-rock interaction: An overview of Sr, B, O, H isotopes and U-series in deep groundwaters from the Vienne granitoid (France); P. Negrel, et al. Water-rock reaction experiments with Black Forest gneiss and granite; K. Bucher, I. Stober. The distribution of rare earth elements and yttrium in water-rock interactions: field observations and experiments; P. Moller. Hydrothermal and volcanic settings. A case study of gas-water-rock interaction in a volcanic aquifer: the south-western flank of Mt. Etna (Sicily); A. Aiuppa, et al. Modelling chemical brine-rock interaction in geothermal reservoirs; M. Kuhn, et al. Mineral deposits. Water-rock reactions in a barite-fluorite underground mine, Black Forest (Germany); I. Stober, et al. Extensional Veins and Pb-Zn Mineralisation in basement rocks: The role of penetration of formation brines; S. Gleeson, B. Yardley. Experimental studies. Interaction of polysilicic and monosilicic acid with mineral surfaces; M. Dietzel.