Over the last fifteen years, space-based exploration of the solar system has increased dramatically, with more and more sophisticated orbiters and landers being sent to Mars. This intense period, rich in unprecedented scientific results, has led to immense progress in our perception of Mars and of its evolution over geological time. In parallel, advances in numerical simulations and laboratory experiments also shed new light on the geochemical evolution of the planet Mars. The ISSI-Europlanet Workshop entitled "Quantifying the Martian Geochemical Reservoirs" was held in Bern in April 2011...