This programme studies the structure and composition of the Earth's interior, the geodynamic processes on the large, planetary scale, and the Earth's gravity and magnetic fields. There is strong interaction between theoretical and computational methods and observational techniques. Seismological (and seismic) studies provide important information concerning the structure and composition of the Earth's interior, on a wide range of spatial scales. Earth-oriented space research provides observations and models of the Earth's gravity field, and hence, implicitly, on the mass distribution in the Earth. Improved gravity field models provided by future gravity field missions such as CHAMP, GRACE and GOCE will open new possibilities for studying geodynamic processes on global and regional scales. Further planetary-scale aspects studied by space-geodetic methods involve tides and currents, and also atmospheric disturbances, relevant for the analysis of loading of the crust/lithosphere and for the vertical motion estimates. Modelling mass and heat transport in the Earth using a computational science approach is another focus of this programme. This encompasses models for the physics and dynamics of planetary interiors, based on non-linear, pressure- and temperature-dependent rheologies, and including the interaction between the mantle and the lithosphere. In this programme, paleomagnetic research focuses on geomagnetic variations and their significance for the dynamics of the Earth's outer core. Through their methodological similarities or a common physical basis with several of the above topics (transport processes, seismology, geopotential fields), hydrological research and the development and application of seismic and potential methods are part of this programme.