Only the uppermost veneer of our planet is directly accessible to instrumental observation. Exploration of the deeper region of our planet relies solely on sophisticated remote sensing. Interpretation of these measurements depends on the results of laboratory and theoretical simulations. With the technological advances of the past two decades (diamond-anvil cell, synchrotron radiation, powerful computers) the picture of the Earth's interior has become more and more precise. Laboratory geophysics -the branch of Earth Science devoted to simulating the various thermal and dynamic processes operating within the Earth- has grown into a mature field of research. With p-T-V data on oxides and silicates   it is now possible to estimate the geothermal gradient in the Earth, construct precise density profiles and even predict the conductive properties  of deep layers within the Earth's mantle.