A renewed era of exploration of the innermost planet began last year with the first two Mercury flybys by the MESSENGER spacecraft. MESSENGER will fly by for a third time in September and will go into orbit around Mercury in 2011, and three years later the BepiColombo mission will launch two spacecraft to orbit Mercury and make extensive measurements of the planet and its environment. Spacecraft results to date are already stimulating new ground-based observations, laboratory measurements, and model calculations. This session is open to all new findings on the science of the innermost planet.