What are the processes that drive magmatic diversity? How is it that volcanic centers can exist for millions of years erupting a variety of chemical types? What are the means by which large batholithic complexes become assembled? Magmas (silicate melts)differ from other geophysical fluids, such as oceans and atmospheres, in that their physiochemical history is largely governed by the processes of solidification and melting. This yields a system with strongly varying physical properties where bouyancy can be generated in complex ways. Much of the recent progress has come from numerical and experimental work specifically directed at the complex interactions of multicomponent systems undergoing phase changes and transport. Geochemical studies also indicate that magmatism is the result of thermal and chemical perturbations on a crustal scale.