Current seismic tomography models are computed using millions of seismograms and  show mutual consistency at increasingly small scales. Yet, tomography’s resolution and discovery potential are nowhere near saturation. The ongoing growth in data sampling enables resolving tectonic-unit structure and tectonic-process deep expressions and drivers. Progress in computational petrology and seismic-data inversion has opened an important new direction: inversion of the data directly for temperature within the Earth, or Seismic Thermography. The mapping of the physical structure and evolution of the lithosphere and underlying mantle illuminates the basic mechanisms that control tectonics, seismicity, magmatism, and the development and distribution of geothermal energy and mineral resources.