The physical behaviour of magmatic systems continues to be a very active area of investigation. Renewed emphasis on the physics of magmas has been fuelled in recent years by events as disparate as the input of comparative planetology into speculations on the role of melting in influencing the chemical, mineralogical and physical evolution of the Earth and the alarming frequency of explosive and effusive volcanic activity in many parts of the globe. Despite the diversity of applications of an adequate physical description of magmas and their transport, we are still quite removed from a satisfactory general model of the physical response of magmas to the wide range of pressure, temperature and stress fields to which they are subjected. Significant efforts have been employed in the Geoinstitut over the past year to improve this situation. The following contributions deal with aspects of the rheology, strength, and equation of state of magmas in processes ranging from melt segregation to explosive volcanism. In particular a balanced view of the roles of ductile versus brittle processes in the deformation of melt-bearing systems seems to be emerging. They underline the advantages contained in combining facilities for the chemical, microstructural and physical characterisation of magma together with a vital experimentation program into the nature of magmatic processes, at the Bayerisches Geoinstitut.