Rob van der Hilst’s cross-disciplinary and collaborative research focuses on understanding geological processes in Earth’s deep interior, both on a regional scale – for instance, continental structure and evolution of Tibet, East Asia, and North America, the subduction of oceanic plates beneath western Pacific island arcs, the upper mantle transition zone beneath Hawaii, and the complex region just above the core mantle boundary beneath Asia and Central America – and the global scale, unraveling, for instance, the pattern and nature of mantle convection. The main tools he uses (and develops) are global reflection seismology and seismic tomography, but he integrates these findings with constraints from geology, (geomagnetic) plate reconstructions, mineral physics, and geodynamics.